"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