OT Ford semi truck, cab heater not working
 

We have a 1985' Ford LNT9000 semi tractor. Its heater used to work. It
was switched by a four position heater switch. It recently stopped
working. I just started troubleshooting this problem, and found it to
be very painful to do, due to cramped panel and complicated wiring
that is hard to access.

So far, I have been able to locate two wires that supply electricity
to the heater fan. If I apply 12v to them, the fan runs vigorously.

The truck, as far as I can see, has no fuses.

From our motor-heads, I wanted to find out what would be the most
typical issue with those fans. Maybe it can help shorten my search for
the trouble. Thanks

OT Ford semi truck, cab heater not working
 

On Fri, 31 Jan 2014 22:38:43 -0600, Ignoramus16088
wrote:

We have a 1985' Ford LNT9000 semi tractor. Its heater used to work. It
was switched by a four position heater switch. It recently stopped
working. I just started troubleshooting this problem, and found it to
be very painful to do, due to cramped panel and complicated wiring
that is hard to access.

So far, I have been able to locate two wires that supply electricity
to the heater fan. If I apply 12v to them, the fan runs vigorously.

The truck, as far as I can see, has no fuses.

You just haven't found them yet. Ford used fusible links on some
things for years, so look for those, too.


From our motor-heads, I wanted to find out what would be the most
typical issue with those fans. Maybe it can help shorten my search for
the trouble. Thanks

I never worked on semis, but the car and truck HVAC switches were
sometimes routed through both vacuum -and- mechanical controls. Your
best bet is to buy a service manual for your exact truck. Libraries
sometimes have them. Or see if your usual truck service manager will
allow you to check the schematics at the shop.

I "grew up" with Mitchell manuals at work and Chilton manuals at home.
Mitchell was $$$$, about $400 a pop, but they had good, solid info.
I want to cry: http://tinyurl.com/kkekhyg but odds it has your big rig
in it are slim to none.

Also check your manuals site. You may have one hiding there. vbg

Oh, here you go: http://tinyurl.com/lpmmnfc

--
I have the consolation of having added nothing to my private fortune during
my public service, and of retiring with hands clean as they are empty.
-- Thomas Jefferson, letter to Count Diodati, 1807

Too bad -none- of the current CONgresscritters are willing to do that. -LJ

OT Ford semi truck, cab heater not working
 

"Ignoramus16088" wrote in message
...
We have a 1985' Ford LNT9000 semi tractor. Its heater used to work. It
was switched by a four position heater switch. It recently stopped
working. I just started troubleshooting this problem, and found it to
be very painful to do, due to cramped panel and complicated wiring
that is hard to access.

So far, I have been able to locate two wires that supply electricity
to the heater fan. If I apply 12v to them, the fan runs vigorously.

The truck, as far as I can see, has no fuses.

From our motor-heads, I wanted to find out what would be the most
typical issue with those fans. Maybe it can help shorten my search for
the trouble. Thanks

http://lmgtfy.com/?q=how+does+a+car+...switch+work%3F

OT Ford semi truck, cab heater not working
 

On 1/31/14, 8:38 PM, Ignoramus16088 wrote:
We have a 1985' Ford LNT9000 semi tractor. Its heater used to work. It
was switched by a four position heater switch. It recently stopped
working. I just started troubleshooting this problem, and found it to
be very painful to do, due to cramped panel and complicated wiring
that is hard to access.

So far, I have been able to locate two wires that supply electricity
to the heater fan. If I apply 12v to them, the fan runs vigorously.

The truck, as far as I can see, has no fuses.

From our motor-heads, I wanted to find out what would be the most
typical issue with those fans. Maybe it can help shorten my search for
the trouble. Thanks


Really no experience with the truck in question... however, blower motor
resistors are a common blower problem with many vehicles... but, the
motor will usually run in the 'high' position with a bad resistor unit.

Also, it almost has to have fuses somewhere... I'd start looking at the
battery Pos terminal... a cable will run to the starter, and another
smaller one to the fuse box. But, the fuse box might be fed from the
starters battery cable terminal. Snoop around, bet you find it.

Also, think about jumping through any & all necessary hoops to procure a
shop manual... it'll pay for it self many times over in
cash/time/frustration as the truck ages.

Good luck!

Erik

OT Ford semi truck, cab heater not working
 

On Friday, January 31, 2014 8:38:43 PM UTC-8, Ignoramus16088 wrote:
We have a 1985' Ford LNT9000 semi tractor. Its heater used to work. It

was switched by a four position heater switch. It recently stopped

working. I just started troubleshooting this problem, and found it to

be very painful to do, due to cramped panel and complicated wiring

that is hard to access.



So far, I have been able to locate two wires that supply electricity

to the heater fan. If I apply 12v to them, the fan runs vigorously.



The truck, as far as I can see, has no fuses.



From our motor-heads, I wanted to find out what would be the most

typical issue with those fans. Maybe it can help shorten my search for

the trouble. Thanks



Here is the Motörhead help you asked for:

http://www.youtube.com/watch?v=1iwC2QljLn4

OT Ford semi truck, cab heater not working
 

On 2/1/2014 12:47 AM, Erik wrote:
On 1/31/14, 8:38 PM, Ignoramus16088 wrote:
We have a 1985' Ford LNT9000 semi tractor. Its heater used to work. It
was switched by a four position heater switch. It recently stopped
working. I just started troubleshooting this problem, and found it to
be very painful to do, due to cramped panel and complicated wiring
that is hard to access.

So far, I have been able to locate two wires that supply electricity
to the heater fan. If I apply 12v to them, the fan runs vigorously.

The truck, as far as I can see, has no fuses.

From our motor-heads, I wanted to find out what would be the most
typical issue with those fans. Maybe it can help shorten my search for
the trouble. Thanks


Really no experience with the truck in question... however, blower motor
resistors are a common blower problem with many vehicles... but, the
motor will usually run in the 'high' position with a bad resistor unit.

Also, it almost has to have fuses somewhere... I'd start looking at the
battery Pos terminal... a cable will run to the starter, and another
smaller one to the fuse box. But, the fuse box might be fed from the
starters battery cable terminal. Snoop around, bet you find it.

Also, think about jumping through any & all necessary hoops to procure a
shop manual... it'll pay for it self many times over in
cash/time/frustration as the truck ages.

Good luck!

Erik

+1. I've had the motor quit completely with a blown resistor. Doesn't
make sense to me either but a new resistor solved the issue.

OT Ford semi truck, cab heater not working
 

On 2014-02-01, Tom Gardner Mars@Tacks wrote:
On 2/1/2014 12:47 AM, Erik wrote:
On 1/31/14, 8:38 PM, Ignoramus16088 wrote:
We have a 1985' Ford LNT9000 semi tractor. Its heater used to work. It
was switched by a four position heater switch. It recently stopped
working. I just started troubleshooting this problem, and found it to
be very painful to do, due to cramped panel and complicated wiring
that is hard to access.

So far, I have been able to locate two wires that supply electricity
to the heater fan. If I apply 12v to them, the fan runs vigorously.

The truck, as far as I can see, has no fuses.

From our motor-heads, I wanted to find out what would be the most
typical issue with those fans. Maybe it can help shorten my search for
the trouble. Thanks


Really no experience with the truck in question... however, blower motor
resistors are a common blower problem with many vehicles... but, the
motor will usually run in the 'high' position with a bad resistor unit.

Also, it almost has to have fuses somewhere... I'd start looking at the
battery Pos terminal... a cable will run to the starter, and another
smaller one to the fuse box. But, the fuse box might be fed from the
starters battery cable terminal. Snoop around, bet you find it.

Also, think about jumping through any & all necessary hoops to procure a
shop manual... it'll pay for it self many times over in
cash/time/frustration as the truck ages.

Good luck!

Erik

+1. I've had the motor quit completely with a blown resistor. Doesn't
make sense to me either but a new resistor solved the issue.

OK, thanks. Where is that resistor usually, under the dash, or in the
engine compartment?

OT Ford semi truck, cab heater not working
 

On 2014-02-01, Gunner Asch wrote:
On Fri, 31 Jan 2014 22:38:43 -0600, Ignoramus16088
wrote:

We have a 1985' Ford LNT9000 semi tractor. Its heater used to work. It
was switched by a four position heater switch. It recently stopped
working. I just started troubleshooting this problem, and found it to
be very painful to do, due to cramped panel and complicated wiring
that is hard to access.

So far, I have been able to locate two wires that supply electricity
to the heater fan. If I apply 12v to them, the fan runs vigorously.

The truck, as far as I can see, has no fuses.

It has fuses. You need to find them

It may..may have breakers..but it has protection of one sort or
another

Now what does that "four position heater switch" do? Off,
low/medium/high?

Yes, this is what it does.

i

OT Ford semi truck, cab heater not working
 

Ignoramus16088 wrote:
We have a 1985' Ford LNT9000 semi tractor. Its heater used to work. It
was switched by a four position heater switch. It recently stopped
working. I just started troubleshooting this problem, and found it to
be very painful to do, due to cramped panel and complicated wiring
that is hard to access.

So far, I have been able to locate two wires that supply electricity
to the heater fan. If I apply 12v to them, the fan runs vigorously.

The truck, as far as I can see, has no fuses.

From our motor-heads, I wanted to find out what would be the most
typical issue with those fans. Maybe it can help shorten my search for
the trouble. Thanks


Fuse/breaker panel is behind the dash panel on the right side I believe.
Been a while since I worked on an L series. Seems like a couple screws
pulls the pad off.

Does the fan blow at all using the switch? Usually high is straight
through?

--
Steve W.

OT Ford semi truck, cab heater not working
 

"Ignoramus23944" wrote in message
...
On 2014-02-01, Tom Gardner Mars@Tacks wrote:
On 2/1/2014 12:47 AM, Erik wrote:
On 1/31/14, 8:38 PM, Ignoramus16088 wrote:
We have a 1985' Ford LNT9000 semi tractor. Its heater used to work. It
was switched by a four position heater switch. It recently stopped
working. I just started troubleshooting this problem, and found it to
be very painful to do, due to cramped panel and complicated wiring
that is hard to access.

So far, I have been able to locate two wires that supply electricity
to the heater fan. If I apply 12v to them, the fan runs vigorously.

The truck, as far as I can see, has no fuses.

From our motor-heads, I wanted to find out what would be the most
typical issue with those fans. Maybe it can help shorten my search for
the trouble. Thanks


Really no experience with the truck in question... however, blower motor
resistors are a common blower problem with many vehicles... but, the
motor will usually run in the 'high' position with a bad resistor unit.

Also, it almost has to have fuses somewhere... I'd start looking at the
battery Pos terminal... a cable will run to the starter, and another
smaller one to the fuse box. But, the fuse box might be fed from the
starters battery cable terminal. Snoop around, bet you find it.

Also, think about jumping through any & all necessary hoops to procure a
shop manual... it'll pay for it self many times over in
cash/time/frustration as the truck ages.

Good luck!

Erik

+1. I've had the motor quit completely with a blown resistor. Doesn't
make sense to me either but a new resistor solved the issue.

OK, thanks. Where is that resistor usually, under the dash, or in the
engine compartment?


on a typical passenger car/truck, in the heater plenum near the blower motor

OT Ford semi truck, cab heater not working
 

On 2014-02-01, Steve W. wrote:
Ignoramus16088 wrote:
We have a 1985' Ford LNT9000 semi tractor. Its heater used to work. It
was switched by a four position heater switch. It recently stopped
working. I just started troubleshooting this problem, and found it to
be very painful to do, due to cramped panel and complicated wiring
that is hard to access.

So far, I have been able to locate two wires that supply electricity
to the heater fan. If I apply 12v to them, the fan runs vigorously.

The truck, as far as I can see, has no fuses.

From our motor-heads, I wanted to find out what would be the most
typical issue with those fans. Maybe it can help shorten my search for
the trouble. Thanks


Fuse/breaker panel is behind the dash panel on the right side I believe.
Been a while since I worked on an L series. Seems like a couple screws
pulls the pad off.

OK, great, I would never guess, it helps a lot.

Does the fan blow at all using the switch? Usually high is straight
through?

No, it does not blow in any position.

i

OT Ford semi truck, cab heater not working
 

Ignoramus23944 wrote:
On 2014-02-01, Steve W. wrote:
Ignoramus16088 wrote:
We have a 1985' Ford LNT9000 semi tractor. Its heater used to work. It
was switched by a four position heater switch. It recently stopped
working. I just started troubleshooting this problem, and found it to
be very painful to do, due to cramped panel and complicated wiring
that is hard to access.

So far, I have been able to locate two wires that supply electricity
to the heater fan. If I apply 12v to them, the fan runs vigorously.

The truck, as far as I can see, has no fuses.

From our motor-heads, I wanted to find out what would be the most
typical issue with those fans. Maybe it can help shorten my search for
the trouble. Thanks

Fuse/breaker panel is behind the dash panel on the right side I believe.
Been a while since I worked on an L series. Seems like a couple screws
pulls the pad off.

OK, great, I would never guess, it helps a lot.

Does the fan blow at all using the switch? Usually high is straight
through?

No, it does not blow in any position.

i

Most likely the switch.
The blower resistors in the older vehicles were only switched in for the
lower speeds, high was direct feed.

You should be able to find the resistor block in the ductwork of the
heater box somewhere near the blower motor. The air across it keeps it
cooled. 2-3 screws and it will come out. You can tell if it's bad
visually, it will be burnt.


--
Steve W.

OT Ford semi truck, cab heater not working
 

"Ignoramus23944" wrote in message
...
On 2014-02-01, Steve W. wrote:
Ignoramus16088 wrote:
We have a 1985' Ford LNT9000 semi tractor. Its heater used to work. It
was switched by a four position heater switch. It recently stopped
working. I just started troubleshooting this problem, and found it to
be very painful to do, due to cramped panel and complicated wiring
that is hard to access.

So far, I have been able to locate two wires that supply electricity
to the heater fan. If I apply 12v to them, the fan runs vigorously.

The truck, as far as I can see, has no fuses.

From our motor-heads, I wanted to find out what would be the most
typical issue with those fans. Maybe it can help shorten my search for
the trouble. Thanks


Fuse/breaker panel is behind the dash panel on the right side I believe.
Been a while since I worked on an L series. Seems like a couple screws
pulls the pad off.

OK, great, I would never guess,

That's because you're too stupid to realize that it's always going to be
located wherever the branch supply harness(es) terminate.

OT Ford semi truck, cab heater not working
 

On Saturday, February 1, 2014 8:52:23 AM UTC-8, Ignoramus23944 wrote:

snip

No, it does not blow in any position.



i

Your posts make it very clear that you're willing to blow anyone who buys from you or that will sell to you for pennies on the dollar.

OT Ford semi truck, cab heater not working
 

"Ignoramus23944" wrote in
message ...
On 2014-02-01, Tom Gardner Mars@Tacks wrote:
On 2/1/2014 12:47 AM, Erik wrote:
On 1/31/14, 8:38 PM, Ignoramus16088 wrote:
We have a 1985' Ford LNT9000 semi tractor. Its heater used to
work. It
was switched by a four position heater switch. It recently
stopped
working. I just started troubleshooting this problem, and found
it to
be very painful to do, due to cramped panel and complicated
wiring
that is hard to access.

So far, I have been able to locate two wires that supply
electricity
to the heater fan. If I apply 12v to them, the fan runs
vigorously.

The truck, as far as I can see, has no fuses.

From our motor-heads, I wanted to find out what would be the
most
typical issue with those fans. Maybe it can help shorten my
search for
the trouble. Thanks


Really no experience with the truck in question... however, blower
motor
resistors are a common blower problem with many vehicles... but,
the
motor will usually run in the 'high' position with a bad resistor
unit.

Also, it almost has to have fuses somewhere... I'd start looking
at the
battery Pos terminal... a cable will run to the starter, and
another
smaller one to the fuse box. But, the fuse box might be fed from
the
starters battery cable terminal. Snoop around, bet you find it.

Also, think about jumping through any & all necessary hoops to
procure a
shop manual... it'll pay for it self many times over in
cash/time/frustration as the truck ages.

Good luck!

Erik

+1. I've had the motor quit completely with a blown resistor.
Doesn't
make sense to me either but a new resistor solved the issue.

OK, thanks. Where is that resistor usually, under the dash, or in
the
engine compartment?

In the air duct, for cooling.

OT Ford semi truck, cab heater not working
 

On Fri, 31 Jan 2014 22:38:43 -0600, Ignoramus16088
wrote:

We have a 1985' Ford LNT9000 semi tractor. Its heater used to work. It
was switched by a four position heater switch. It recently stopped
working. I just started troubleshooting this problem, and found it to
be very painful to do, due to cramped panel and complicated wiring
that is hard to access.

So far, I have been able to locate two wires that supply electricity
to the heater fan. If I apply 12v to them, the fan runs vigorously.

The truck, as far as I can see, has no fuses.

From our motor-heads, I wanted to find out what would be the most
typical issue with those fans. Maybe it can help shorten my search for
the trouble. Thanks
The LNT WILL have fuses somewhere.
should be on passenger side dash, there are two screws near the
windshield and then the cover flips open, fuses in there.

OT Ford semi truck, cab heater not working
 

"Ignoramus23944" wrote in
message ...
On 2014-02-01, Steve W. wrote:
Ignoramus16088 wrote:
We have a 1985' Ford LNT9000 semi tractor. Its heater used to
work. It
was switched by a four position heater switch. It recently stopped
working. I just started troubleshooting this problem, and found it
to
be very painful to do, due to cramped panel and complicated wiring
that is hard to access.

So far, I have been able to locate two wires that supply
electricity
to the heater fan. If I apply 12v to them, the fan runs
vigorously.

The truck, as far as I can see, has no fuses.

From our motor-heads, I wanted to find out what would be the most
typical issue with those fans. Maybe it can help shorten my search
for
the trouble. Thanks


Fuse/breaker panel is behind the dash panel on the right side I
believe.
Been a while since I worked on an L series. Seems like a couple
screws
pulls the pad off.

OK, great, I would never guess, it helps a lot.

Does the fan blow at all using the switch? Usually high is straight
through?

No, it does not blow in any position.

i

The blower motor in my '91 slows down and needs re-oiling
occasionally. I drilled small holes for a needle oiler in the end caps
and cover them with aluminum tape.
jsw

OT Ford semi truck, cab heater not working
 

On 2014-02-01, Ignoramus16088 wrote:
We have a 1985' Ford LNT9000 semi tractor. Its heater used to work. It
was switched by a four position heater switch. It recently stopped
working. I just started troubleshooting this problem, and found it to
be very painful to do, due to cramped panel and complicated wiring
that is hard to access.

So far, I have been able to locate two wires that supply electricity
to the heater fan. If I apply 12v to them, the fan runs vigorously.

Good -- the brushes are not worn out yet, then.

The truck, as far as I can see, has no fuses.

Anywhere? There should be a number of them *somewhere* --
including fuses for the power feed connector to the trailer.

From our motor-heads, I wanted to find out what would be the most
typical issue with those fans. Maybe it can help shorten my search for
the trouble. Thanks

First -- a question:

Does it perhaps run -- only when set to high speed?

I don't know the semi tractor, but I have some experience with a
similar problem in a '96 Mazda Navajo (really a Ford Explorer), and Ford
may do things pretty much the same way over a period of time.

The one in question accomplished the speed control by low valued
resistance elements in the airflow -- an assembly installed into the fan
housing. The problem cause: Squirrels or maybe mice building a nest in
there and partially blocking the airflow. This deprived the resistance
elements of the cooling airflow, and they started sending smoke into the
cab. If switched to high speed at the first sign of smoke, the added
airflow (and bypassing all the resistance elements) allowed it to
continue working. This first happened when my wife was driving it, and
when I looked at it, I discovered the work-around of running the motor
full speed. If it is this -- look for a multi-pin connector snapped
onto the outside of the fan housing. (Is the fan housing under the hood,
or hidden under the dash?

It was a real pain to get to the resistance element and remove
it. Two long screws with very little access, even with the connector
unplugged. The actual replacement element was quite inexpensive.

Now -- the multi-speed assembly probably works the same way in
your older (and much larger) semi, but the resistance elements may not
be in the airflow path to the cab. They may be just somewhere under the
hood. The trick is finding them.

Wiring is sort of like this:

+12---------o----o-- (OFF)



o---WWW--+ (Low)
|
+------+
|
o-+-WWW--+ (Medium)
|
+------+
|
o-+-WWW--+ (Sorta High)
|
|
| (Full Speed)
o--------+------(Fan Motor) ---ground

and the resistance elements are simply coils of bare wire, with the
highest speed before full being a rather short coil of heavy wire, and
each lower speed adding another longer coil of smaller wire, but not too
many turns in any of them.

Look for the resistor assembly. If you can find it, it is
likely to be the problem point, especially if the fan run from the raw
12V sounds faster than you remember from before.

Enjoy,
DoN.

--
Remove oil spill source from e-mail
Email: | (KV4PH) Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

OT Ford semi truck, cab heater not working
 

Ignoramus16088 wrote:

We have a 1985' Ford LNT9000 semi tractor. Its heater used to work. It
was switched by a four position heater switch. It recently stopped
working. I just started troubleshooting this problem, and found it to
be very painful to do, due to cramped panel and complicated wiring
that is hard to access.

So far, I have been able to locate two wires that supply electricity
to the heater fan. If I apply 12v to them, the fan runs vigorously.

OK, so the problem is the fan doesn't run? Anything 1985 vintage would
not have electronic speed controls, but probably has a resistor
unit that is in the airflow path. So, poke around the fan assembly
looking for a block with some wires attached. Pull it, and you
will likely see some coils of resistor wire, and likely a one-time
thermal fuse. If the fan motor stalls or the airflow is restricted,
the resistor unit burns up, and the thermal fuse often is wired to kill
even the high-speed setting. These resistor units are fan-cooled,
so they have to be in the air path.

And, of course, there HAVE to be fuses somewhere.

Jon

OT Ford semi truck, cab heater not working
 

Ignoramus23944 writes:


OK, thanks. Where is that resistor usually, under the dash, or in the
engine compartment?

It's somewhere in the airstream of the heater system. If the
blower is on but not spinning [i.e. jammed], the resister often
dies a quick death. But the fastest position has no resistor in
series; so if that is also dead, look elsewhere.

--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

OT Ford semi truck, cab heater not working
 

On 2014-02-02, Jon Elson wrote:
Ignoramus16088 wrote:

We have a 1985' Ford LNT9000 semi tractor. Its heater used to work. It
was switched by a four position heater switch. It recently stopped
working. I just started troubleshooting this problem, and found it to
be very painful to do, due to cramped panel and complicated wiring
that is hard to access.

So far, I have been able to locate two wires that supply electricity
to the heater fan. If I apply 12v to them, the fan runs vigorously.

OK, so the problem is the fan doesn't run? Anything 1985 vintage would
not have electronic speed controls, but probably has a resistor
unit that is in the airflow path. So, poke around the fan assembly
looking for a block with some wires attached. Pull it, and you
will likely see some coils of resistor wire, and likely a one-time
thermal fuse. If the fan motor stalls or the airflow is restricted,
the resistor unit burns up, and the thermal fuse often is wired to kill
even the high-speed setting. These resistor units are fan-cooled,
so they have to be in the air path.

This is a good start. I am going to work tomorrow and I will work on
this semi tractor. It is parked inside, thankfully.

i

And, of course, there HAVE to be fuses somewhere.

Jon

OT Ford semi truck, cab heater not working
 

Ignoramus23944 wrote:


This is a good start. I am going to work tomorrow and I will work on
this semi tractor. It is parked inside, thankfully.
OH, that makes it MUCH easier to work on!

Jon

OT Ford semi truck, cab heater not working
 

On Saturday, February 1, 2014 8:35:38 PM UTC-8, Ignoramus23944 wrote:

This is a good start. I am going to work tomorrow and I will work on

this semi tractor. It is parked inside, thankfully.



i

Put it outside. It can only be fixed outside.

OT Ford semi truck, cab heater not working
 

OK, guys, thanks a lot. I spent some time today with the truck.

It was just like you said: fuses on the right side of the panel,
heater switch working with resistors, etc.

The problem was, I think, a switch connector coming apart for any
reason (possibly people messing with the panel where the heater switch
is). Everything is back together and the heater fan works, at least in
high.

i

OT Ford semi truck, cab heater not working
 

On 2/2/14, 7:16 PM, Ignoramus24227 wrote:
OK, guys, thanks a lot. I spent some time today with the truck.

It was just like you said: fuses on the right side of the panel,
heater switch working with resistors, etc.

The problem was, I think, a switch connector coming apart for any
reason (possibly people messing with the panel where the heater switch
is). Everything is back together and the heater fan works, at least in
high.

i


Glad your up and going!

Erik

OT Ford semi truck, cab heater not working
 

On Sun, 02 Feb 2014 21:16:15 -0600, Ignoramus24227
wrote:

OK, guys, thanks a lot. I spent some time today with the truck.

It was just like you said: fuses on the right side of the panel,
heater switch working with resistors, etc.

The problem was, I think, a switch connector coming apart for any
reason (possibly people messing with the panel where the heater switch
is). Everything is back together and the heater fan works, at least in
high.

i

If it works in high and maybe in Med-Hi, but the other speeds are
dead, that's the resistor pack or the switch. Get out your ohm-meter
and see which.

-- Bruce --

OT Ford semi truck, cab heater not working
 

On 2014-02-03, Ignoramus24227 wrote:
OK, guys, thanks a lot. I spent some time today with the truck.

It was just like you said: fuses on the right side of the panel,
heater switch working with resistors, etc.

The problem was, I think, a switch connector coming apart for any
reason (possibly people messing with the panel where the heater switch
is). Everything is back together and the heater fan works, at least in
high.

If it runs in high *only*, then the resistors are certainly the
problem. Just find where it is (somewhere in the housing (ducting)
carrying airflow from the fan to the cab -- likely fairly close to it.
Look for a multi-pin connector on the ducting. Pull the connector, and
you will see (likely) two screws holding it to the ducting. If you are
lucky, it doesn't require tiny hands to get to the screws, and big
strong hands to turn the wrench -- that is certainly the problem on a
'95 Mazda Navajo (Ford Explorer clone, IIRC).

Since the problem showed up in mid-winter, and I (unlike you)
did not have an indoor place to work on it, it got run on high or off
until the summertime. :-)

Good Luck,
DoN.

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