I have a car Fiesta 1.3 Endura 2001 – 2002.
It is fitted with a Ford CD car radio.
Up until two days ago the car radio worked fine (and it still does ).
Here's the problem; –
about 18 months ago the rear screen heater stopped working.
I looked at it and couldn't see anything obvious. I checked the
connectors and the switch and the fuses. put to one side to do when I
could fit it in.

On Saturday I got the workshop manual out and the multimeter. 10 minutes
late I locate the problem, the relay which is mounted up behind the fuse
box appears to not work. Upon examination of the relay the high current
terminal has overheated and gone open circuit. Cleaned up and swapped
that relay for another one of the same type mounted in the same fuse box
checked circuits and it's okay.

Later that day I go to Tesco's and radio isn't working very well, low
signal.
I think to myself that's funny! Just out of interest I turn off the rear
screen heater. The radio now works. So I turn the heat back on again,
and the radio goes hissy, turn it off and the radio is fine.

I've rechecked that the rear screen circuits are all intact and not
arcing or anything but it got me beat (that's not hard).
Any ideas ?

On Tuesday, December 11, 2012 1:16:58 PM UTC, Gary wrote:
I have a car Fiesta 1.3 Endura 2001 – 2002.

It is fitted with a Ford CD car radio.

Up until two days ago the car radio worked fine (and it still does ).

Here's the problem; –

about 18 months ago the rear screen heater stopped working.

I looked at it and couldn't see anything obvious. I checked the

connectors and the switch and the fuses. put to one side to do when I

could fit it in.



On Saturday I got the workshop manual out and the multimeter. 10 minutes

late I locate the problem, the relay which is mounted up behind the fuse

box appears to not work. Upon examination of the relay the high current

terminal has overheated and gone open circuit. Cleaned up and swapped

that relay for another one of the same type mounted in the same fuse box

checked circuits and it's okay.



Later that day I go to Tesco's and radio isn't working very well, low

signal.

I think to myself that's funny! Just out of interest I turn off the rear

screen heater. The radio now works. So I turn the heat back on again,

and the radio goes hissy, turn it off and the radio is fine.



I've rechecked that the rear screen circuits are all intact and not

arcing or anything but it got me beat (that's not hard).

Any ideas ?

The drain on the battery from the working heater is causing the radio problems, maybe the car battery is on it's way out, have you tried measuring the voltage when the heaters on. Clucthcing at straws perhaps

I'd blame the cold weather ;-)

On 11/12/2012 13:24, whisky-dave wrote:
On Tuesday, December 11, 2012 1:16:58 PM UTC, Gary wrote:
I have a car Fiesta 1.3 Endura 2001 – 2002.

It is fitted with a Ford CD car radio.

Up until two days ago the car radio worked fine (and it still does ).

Here's the problem; –

about 18 months ago the rear screen heater stopped working.

I looked at it and couldn't see anything obvious. I checked the

connectors and the switch and the fuses. put to one side to do when I

could fit it in.



On Saturday I got the workshop manual out and the multimeter. 10 minutes

late I locate the problem, the relay which is mounted up behind the fuse

box appears to not work. Upon examination of the relay the high current

terminal has overheated and gone open circuit. Cleaned up and swapped

that relay for another one of the same type mounted in the same fuse box

checked circuits and it's okay.



Later that day I go to Tesco's and radio isn't working very well, low

signal.

I think to myself that's funny! Just out of interest I turn off the rear

screen heater. The radio now works. So I turn the heat back on again,

and the radio goes hissy, turn it off and the radio is fine.



I've rechecked that the rear screen circuits are all intact and not

arcing or anything but it got me beat (that's not hard).

Any ideas ?
The drain on the battery from the working heater is causing the radio problems, maybe the car battery is on it's way out, have you tried measuring the voltage when the heaters on. Clucthcing at straws perhaps

I'd blame the cold weather ;-)
full voltage. it is as if the aerial amp is being turned off. it is
prosibly an earth problem but it is not obvious where to look.

thanks

What was the other relay being used for that he nicked though, kind of makes
you wonder....
Some cars do use the screen heaters as an aerial. Ther eis usually though
chokes in the circuit to stop problems with the apparent earthing of the
other end of the heater!

Brian
Brian

--
From the Sofa of Brian Gaff Reply address is active
"whisky-dave" wrote in message
...
On Tuesday, December 11, 2012 1:16:58 PM UTC, Gary wrote:
I have a car Fiesta 1.3 Endura 2001 – 2002.

It is fitted with a Ford CD car radio.

Up until two days ago the car radio worked fine (and it still does ).

Here's the problem; –

about 18 months ago the rear screen heater stopped working.

I looked at it and couldn't see anything obvious. I checked the

connectors and the switch and the fuses. put to one side to do when I

could fit it in.



On Saturday I got the workshop manual out and the multimeter. 10 minutes

late I locate the problem, the relay which is mounted up behind the fuse

box appears to not work. Upon examination of the relay the high current

terminal has overheated and gone open circuit. Cleaned up and swapped

that relay for another one of the same type mounted in the same fuse box

checked circuits and it's okay.



Later that day I go to Tesco's and radio isn't working very well, low

signal.

I think to myself that's funny! Just out of interest I turn off the rear

screen heater. The radio now works. So I turn the heat back on again,

and the radio goes hissy, turn it off and the radio is fine.



I've rechecked that the rear screen circuits are all intact and not

arcing or anything but it got me beat (that's not hard).

Any ideas ?

The drain on the battery from the working heater is causing the radio
problems, maybe the car battery is on it's way out, have you tried measuring
the voltage when the heaters on. Clucthcing at straws perhaps

I'd blame the cold weather ;-)

Vehicles are indeed strange things..


--
From the Sofa of Brian Gaff Reply address is active
"whisky-dave" wrote in message
...
On Tuesday, December 11, 2012 1:16:58 PM UTC, Gary wrote:
I have a car Fiesta 1.3 Endura 2001 – 2002.

It is fitted with a Ford CD car radio.

Up until two days ago the car radio worked fine (and it still does ).

Here's the problem; –

about 18 months ago the rear screen heater stopped working.

I looked at it and couldn't see anything obvious. I checked the

connectors and the switch and the fuses. put to one side to do when I

could fit it in.



On Saturday I got the workshop manual out and the multimeter. 10 minutes

late I locate the problem, the relay which is mounted up behind the fuse

box appears to not work. Upon examination of the relay the high current

terminal has overheated and gone open circuit. Cleaned up and swapped

that relay for another one of the same type mounted in the same fuse box

checked circuits and it's okay.



Later that day I go to Tesco's and radio isn't working very well, low

signal.

I think to myself that's funny! Just out of interest I turn off the rear

screen heater. The radio now works. So I turn the heat back on again,

and the radio goes hissy, turn it off and the radio is fine.



I've rechecked that the rear screen circuits are all intact and not

arcing or anything but it got me beat (that's not hard).

Any ideas ?

The drain on the battery from the working heater is causing the radio
problems, maybe the car battery is on it's way out, have you tried measuring
the voltage when the heaters on. Clucthcing at straws perhaps

I'd blame the cold weather ;-)

In article ,
Gary wrote:
Later that day I go to Tesco's and radio isn't working very well, low
signal.
I think to myself that's funny! Just out of interest I turn off the rear
screen heater. The radio now works. So I turn the heat back on again,
and the radio goes hissy, turn it off and the radio is fine.

I've rechecked that the rear screen circuits are all intact and not
arcing or anything but it got me beat (that's not hard).
Any ideas ?

Does it use the rear screen element as an aerial? If so perhaps the
amplifier/isolator unit is not being powered correctly after your repair.

--
*I thought I wanted a career. Turns out I just wanted paychecks.

Dave Plowman London SW
To e-mail, change noise into sound.

On 11/12/2012 13:54, Dave Plowman (News) wrote:
In article ,
Gary wrote:
Later that day I go to Tesco's and radio isn't working very well, low
signal.
I think to myself that's funny! Just out of interest I turn off the rear
screen heater. The radio now works. So I turn the heat back on again,
and the radio goes hissy, turn it off and the radio is fine.

I've rechecked that the rear screen circuits are all intact and not
arcing or anything but it got me beat (that's not hard).
Any ideas ?

Does it use the rear screen element as an aerial? If so perhaps the
amplifier/isolator unit is not being powered correctly after your repair.

Or perhaps the original relay damage was caused by failure of the choke
that isolated the element's power supply from its aerial function, so
now when powered, you are in effect grounding your aerial as well?


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Tue, 11 Dec 2012 14:36:08 +0000, John Rumm wrote:

On 11/12/2012 13:54, Dave Plowman (News) wrote:
In article ,
Gary wrote:
Later that day I go to Tesco's and radio isn't working very well, low
signal.
I think to myself that's funny! Just out of interest I turn off the rear
screen heater. The radio now works. So I turn the heat back on again,
and the radio goes hissy, turn it off and the radio is fine.

I've rechecked that the rear screen circuits are all intact and not
arcing or anything but it got me beat (that's not hard).
Any ideas ?

Does it use the rear screen element as an aerial? If so perhaps the
amplifier/isolator unit is not being powered correctly after your repair.

Or perhaps the original relay damage was caused by failure of the choke
that isolated the element's power supply from its aerial function, so
now when powered, you are in effect grounding your aerial as well?

A capacitor will also be needed to isolate any DC from the aerial input.



--
Regards, Paul Herber, Sandrila Ltd.
http://www.sandrila.co.uk/ twitter: @sandrilaLtd

"Brian Gaff" wrote...
On Saturday I got the workshop manual out and the multimeter. 10 minutes
late I locate the problem, the relay which is mounted up behind the fuse
box appears to not work. Upon examination of the relay the high current
terminal has overheated and gone open circuit. Cleaned up and swapped
that relay for another one of the same type mounted in the same fuse box
checked circuits and it's okay.
Later that day I go to Tesco's and radio isn't working very well, low
signal.
I think to myself that's funny! Just out of interest I turn off the rear
screen heater. The radio now works. So I turn the heat back on again,
and the radio goes hissy, turn it off and the radio is fine.

I've rechecked that the rear screen circuits are all intact and not
arcing or anything but it got me beat (that's not hard).
Any ideas ?

The drain on the battery from the working heater is causing the radio
problems, maybe the car battery is on it's way out, have you tried
measuring the voltage when the heaters on. Clucthcing at straws perhaps


I suspect it uses the rear heater element (tracks on the window, like my
Honda had) as the aerial - and the original relay may have an inductor or
similar on one or both of the "heat" terminals to prevent the radio signal
being shorted by the car's electrical system - when the heater comes on one
end of the element is effectively earthed, so you lose most of the signal.
You may need to get an *exactly match* for the relay you took out, or you
could look at adding an inductor in the lead from relay to element?

Dave H, (the other one)

Gary formulated on Tuesday :
I have a car Fiesta 1.3 Endura 2001 €“ 2002.
It is fitted with a Ford CD car radio.
Up until two days ago the car radio worked fine (and it still does ).
Here's the problem; €“
about 18 months ago the rear screen heater stopped working.
I looked at it and couldn't see anything obvious. I checked the connectors
and the switch and the fuses. put to one side to do when I could fit it in.

On Saturday I got the workshop manual out and the multimeter. 10 minutes late
I locate the problem, the relay which is mounted up behind the fuse box
appears to not work. Upon examination of the relay the high current terminal
has overheated and gone open circuit. Cleaned up and swapped that relay for
another one of the same type mounted in the same fuse box checked circuits
and it's okay.

Later that day I go to Tesco's and radio isn't working very well, low signal.
I think to myself that's funny! Just out of interest I turn off the rear
screen heater. The radio now works. So I turn the heat back on again, and the
radio goes hissy, turn it off and the radio is fine.

I've rechecked that the rear screen circuits are all intact and not arcing or
anything but it got me beat (that's not hard).
Any ideas ?

Assuming as many do today - the rear screen heater is used as the
antenna for the radio and the printed tracks on the glass are damaged,
the poor tracks will generate masses of interference when the screen
heater is turned on.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On 11/12/2012 15:36, Harry Bloomfield wrote:
Gary formulated on Tuesday :

snip

I've rechecked that the rear screen circuits are all intact and not
arcing or anything but it got me beat (that's not hard).
Any ideas ?

Assuming as many do today - the rear screen heater is used as the
antenna for the radio and the printed tracks on the glass are damaged,
the poor tracks will generate masses of interference when the screen
heater is turned on.


Why? We're talking 12V here, not a voltage that is going to jump some
distance.

Is there is a bad connection, then it would still show when the heater
is turned off.

On 11/12/2012 14:44, Paul Herber wrote:
On Tue, 11 Dec 2012 14:36:08 +0000, John Rumm wrote:

On 11/12/2012 13:54, Dave Plowman (News) wrote:
In article ,
Gary wrote:
Later that day I go to Tesco's and radio isn't working very well, low
signal.
I think to myself that's funny! Just out of interest I turn off the rear
screen heater. The radio now works. So I turn the heat back on again,
and the radio goes hissy, turn it off and the radio is fine.

I've rechecked that the rear screen circuits are all intact and not
arcing or anything but it got me beat (that's not hard).
Any ideas ?

Does it use the rear screen element as an aerial? If so perhaps the
amplifier/isolator unit is not being powered correctly after your repair.

Or perhaps the original relay damage was caused by failure of the choke
that isolated the element's power supply from its aerial function, so
now when powered, you are in effect grounding your aerial as well?

A capacitor will also be needed to isolate any DC from the aerial input.

Yup, although there is a fair chance the radio will have that internally.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In article ,
John Rumm wrote:
Or perhaps the original relay damage was caused by failure of the
choke that isolated the element's power supply from its aerial
function, so now when powered, you are in effect grounding your
aerial as well?

A capacitor will also be needed to isolate any DC from the aerial
input.

Yup, although there is a fair chance the radio will have that internally.

The installations I've seen that use the rear screen as an aerial have an
amp mounted close to it - which I assume removes all the nasties before
sending it off to the head unit.

--
*If at first you don't succeed, then skydiving definitely isn't for you *

Dave Plowman London SW
To e-mail, change noise into sound.

On Dec 11, 3:36*pm, Harry Bloomfield
wrote:
Gary formulated on Tuesday :

Assuming as many do today - the rear screen heater is used as the
antenna for the radio and the printed tracks on the glass are damaged,
the poor tracks will generate masses of interference when the screen
heater is turned on.

We have that problem on an ancient Skoda which does have a separate
radio aerial.

Jonathan

On Tue, 11 Dec 2012 15:31:17 -0000, "news.virginmedia.com"
wrote:


"Brian Gaff" wrote...
On Saturday I got the workshop manual out and the multimeter. 10 minutes
late I locate the problem, the relay which is mounted up behind the fuse
box appears to not work. Upon examination of the relay the high current
terminal has overheated and gone open circuit. Cleaned up and swapped
that relay for another one of the same type mounted in the same fuse box
checked circuits and it's okay.
Later that day I go to Tesco's and radio isn't working very well, low
signal.
I think to myself that's funny! Just out of interest I turn off the rear
screen heater. The radio now works. So I turn the heat back on again,
and the radio goes hissy, turn it off and the radio is fine.

I've rechecked that the rear screen circuits are all intact and not
arcing or anything but it got me beat (that's not hard).
Any ideas ?

The drain on the battery from the working heater is causing the radio
problems, maybe the car battery is on it's way out, have you tried
measuring the voltage when the heaters on. Clucthcing at straws perhaps


I suspect it uses the rear heater element (tracks on the window, like my
Honda had) as the aerial - and the original relay may have an inductor or
similar on one or both of the "heat" terminals to prevent the radio signal
being shorted by the car's electrical system - when the heater comes on one
end of the element is effectively earthed, so you lose most of the signal.
You may need to get an *exactly match* for the relay you took out, or you
could look at adding an inductor in the lead from relay to element?

Dave H, (the other one)



That's what I thought too. I presume there isn't a conventional aerial
on this car so it's a good guess that the heated rear window is
providing this function. If so, there will be a couple of RF chokes to
isolate the screen at RF, the only problem is that I would expect
these chokes to be near the screen, not under the dash or in the
engine compartment.

Incidentally I had a Civic with that arrangement for a while, I hated
the car for various reasons, but the radio reception on AM and FM was
superb.

--
Graham.
%Profound_observation%

Fredxx formulated the question :
On 11/12/2012 15:36, Harry Bloomfield wrote:
Gary formulated on Tuesday :

snip

I've rechecked that the rear screen circuits are all intact and not
arcing or anything but it got me beat (that's not hard).
Any ideas ?

Assuming as many do today - the rear screen heater is used as the
antenna for the radio and the printed tracks on the glass are damaged,
the poor tracks will generate masses of interference when the screen
heater is turned on.


Why? We're talking 12V here, not a voltage that is going to jump some
distance.

Is there is a bad connection, then it would still show when the heater is
turned off.

I can assure you I do not what I am talking about.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

In article
,
Jonathan wrote:
On Dec 11, 3:36 pm, Harry Bloomfield
wrote:
Gary formulated on Tuesday :

Assuming as many do today - the rear screen heater is used as the
antenna for the radio and the printed tracks on the glass are damaged,
the poor tracks will generate masses of interference when the screen
heater is turned on.

We have that problem on an ancient Skoda which does have a separate
radio aerial.

when I think about it, I had that problem on my no-so-ancient Citröen (only
10½ years). This had a separate roof aerial at the rear of the car.
Replacing the aerial cured the problem. It had broken internally - probably
because it got bent rather severely when I carried sheets of plywood on the
roof bars.

--
From KT24

Using a RISC OS computer running v5.18

In article ,
Gary writes:
I have a car Fiesta 1.3 Endura 2001 – 2002.
It is fitted with a Ford CD car radio.
Up until two days ago the car radio worked fine (and it still does ).
Here's the problem; –
about 18 months ago the rear screen heater stopped working.
I looked at it and couldn't see anything obvious. I checked the
connectors and the switch and the fuses. put to one side to do when I
could fit it in.

On Saturday I got the workshop manual out and the multimeter. 10 minutes
late I locate the problem, the relay which is mounted up behind the fuse
box appears to not work. Upon examination of the relay the high current
terminal has overheated and gone open circuit. Cleaned up and swapped
that relay for another one of the same type mounted in the same fuse box
checked circuits and it's okay.

Later that day I go to Tesco's and radio isn't working very well, low
signal.
I think to myself that's funny! Just out of interest I turn off the rear
screen heater. The radio now works. So I turn the heat back on again,
and the radio goes hissy, turn it off and the radio is fine.

I've rechecked that the rear screen circuits are all intact and not
arcing or anything but it got me beat (that's not hard).

A common problem with older Fiestas is that the earth return
from the rear heater (and rear wiper if you have one) is via
the boot lid hinges, and they go high impedance. Connecting
an earthing strap between the boot lid and the car body fixes
this. Don't know if it's related to your aerial problem though.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 11/12/12 16:06, John Rumm wrote:
On 11/12/2012 14:44, Paul Herber wrote:
On Tue, 11 Dec 2012 14:36:08 +0000, John Rumm
wrote:

On 11/12/2012 13:54, Dave Plowman (News) wrote:
In article ,
Gary wrote:
Later that day I go to Tesco's and radio isn't working very well, low
signal.
I think to myself that's funny! Just out of interest I turn off the
rear
screen heater. The radio now works. So I turn the heat back on again,
and the radio goes hissy, turn it off and the radio is fine.

I've rechecked that the rear screen circuits are all intact and not
arcing or anything but it got me beat (that's not hard).
Any ideas ?

Does it use the rear screen element as an aerial? If so perhaps the
amplifier/isolator unit is not being powered correctly after your
repair.

Or perhaps the original relay damage was caused by failure of the choke
that isolated the element's power supply from its aerial function, so
now when powered, you are in effect grounding your aerial as well?

A capacitor will also be needed to isolate any DC from the aerial input.

Yup, although there is a fair chance the radio will have that internally.


standard input is either a coil to ground, which would smoke on DC, or a
low value kerpuffitor, which will block it.


--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.

On 11/12/2012 17:04, Graham. wrote:
On Tue, 11 Dec 2012 15:31:17 -0000, "news.virginmedia.com"
wrote:


"Brian Gaff" wrote...
On Saturday I got the workshop manual out and the multimeter. 10 minutes
late I locate the problem, the relay which is mounted up behind the fuse
box appears to not work. Upon examination of the relay the high current
terminal has overheated and gone open circuit. Cleaned up and swapped
that relay for another one of the same type mounted in the same fuse box
checked circuits and it's okay.
Later that day I go to Tesco's and radio isn't working very well, low
signal.
I think to myself that's funny! Just out of interest I turn off the rear
screen heater. The radio now works. So I turn the heat back on again,
and the radio goes hissy, turn it off and the radio is fine.

I've rechecked that the rear screen circuits are all intact and not
arcing or anything but it got me beat (that's not hard).
Any ideas ?

The drain on the battery from the working heater is causing the radio
problems, maybe the car battery is on it's way out, have you tried
measuring the voltage when the heaters on. Clucthcing at straws perhaps


I suspect it uses the rear heater element (tracks on the window, like my
Honda had) as the aerial - and the original relay may have an inductor or
similar on one or both of the "heat" terminals to prevent the radio signal
being shorted by the car's electrical system - when the heater comes on one
end of the element is effectively earthed, so you lose most of the signal.
You may need to get an *exactly match* for the relay you took out, or you
could look at adding an inductor in the lead from relay to element?

Dave H, (the other one)



That's what I thought too. I presume there isn't a conventional aerial
on this car so it's a good guess that the heated rear window is
providing this function. If so, there will be a couple of RF chokes to
isolate the screen at RF, the only problem is that I would expect
these chokes to be near the screen, not under the dash or in the
engine compartment.

Incidentally I had a Civic with that arrangement for a while, I hated
the car for various reasons, but the radio reception on AM and FM was
superb.

You used to be able to buy one as an add on. It was a grey, plastic tube
with red ends and a bracket, plus flying leads for connecting the screen
power and the aerial to. About the size of an old style ignition coil.
Mine worked very well in my Sierra.

SteveW

On 11/12/2012 17:06, Harry Bloomfield wrote:
I can assure you I do not what I am talking about.

I'm afraid that I don't.

Andy
--
fx cue skitt

Andy Champ laid this down on his screen :
On 11/12/2012 17:06, Harry Bloomfield wrote:
I can assure you I do not what I am talking about.

I'm afraid that I don't.

Andy

not = know :-)

The point I was trying to make earlier, is that damaged and intermitant
rear screen demister tracks can and do cause lots of interference to
radio reception, especially if the tracks of the demister are used as
an antenna. It has nothing what so ever to do with HV jumping gaps in
the tracks, the damage simply needs to be sufficient to make the track
intermitant.

A very well known issue.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On 11/12/2012 17:08, charles wrote:
In article
,
Jonathan wrote:
On Dec 11, 3:36 pm, Harry Bloomfield
wrote:
Gary formulated on Tuesday :

Assuming as many do today - the rear screen heater is used as the
antenna for the radio and the printed tracks on the glass are damaged,
the poor tracks will generate masses of interference when the screen
heater is turned on.

We have that problem on an ancient Skoda which does have a separate
radio aerial.
when I think about it, I had that problem on my no-so-ancient Citröen (only
10½ years). This had a separate roof aerial at the rear of the car.
Replacing the aerial cured the problem. It had broken internally - probably
because it got bent rather severely when I carried sheets of plywood on the
roof bars.

We have a roof aerial so I shall check it properly now you have said that.