BX heated rear screen

siestaman · Post by **siestaman** » 30 Sep 2003, 20:14

I've just purchased a '91 BX16TRS with 59k on the clock and the only problem with it is that if you press the heated rear screen button the fuse blows.
I've removed the switch and the horn works OK.
I've disconnected the rear screen connectors on the rear screen. Blows the fuse still if I press the switch.
Replaced the rear screen heater relay (R4) fuse still blows when you press the switch.
Replaced the switch (twice) and still the fuse blows!
What's next? Can anyone offer a cure or a suggestion?
[8)][:I]

tomsheppard · Post by **tomsheppard** » 30 Sep 2003, 20:27

between the switch and the window terminal, there is a short circuit to earth. a test with a meter will confirm .

siestaman · Post by **siestaman** » 30 Sep 2003, 20:49

Update:-
If I remove the relay R4 then the fuse doesn't blow.
I do not have a wiring diagram at this time.
Can anyone assist me to locate the short-circuit that might be a trapped wire?
Many thanks.

AndersDK · Post by **AndersDK** » 30 Sep 2003, 20:55

Further - adding to Tom's suggestion :
The flat multi-ribbon cable running under the carpets to the boot - feeds all the rear lights and the rear heated window.
Physically inspect this cable over it's entire run.
Large change the cable is chafed where it run's under the rear seat squabs.
You may want to replace the entire cable - it easily unplugs with a multi connector in the fuse box - and behind the rear left lights cluster. Large chance a good cable to be found from a breakers yard.
But check the "new" cable first - no fun to encounter new problems !

siestaman · Post by **siestaman** » 30 Sep 2003, 21:12

Update:-
On the main fuse panel with relay R4 out and the rear screen switch removed.
The top terminal socket (5) reads short to earth with a meter.
The terminal socket for (2) reads s/c to earth with a meter.
The other 2 sockets (1)(3) on the R4 relay socket read high.
What colour wire goes to (5)?
What colour wire goes to (2)?
Should (5) read s/c?
Should (2) read s/c?
Anyone had this problem before?
Any help is very welcomed!!!

jeremy · Post by **jeremy** » 30 Sep 2003, 21:37

I would first have a look at the cable going between the bodywork and the door and see if it has become damaged. I would then disconnect it if possible and see if the fuse still blow. (There may be a junction somewhere near the nearside light cluster - I am not certain on this)
have a look at the electrical section on this siet. I know its for 16 valves but rear windows are the same.
http://www.rwbsmith.plus.com/citroen2/
Jeremy

siestaman · Post by **siestaman** » 30 Sep 2003, 22:22

Problem found:-
Wiring behind the tailgate.
Somehow the license plate lamp holder was damaged. Possibly when someone changed the bulb. One terminal broke loose and contacted the other terminal. A fuse of the wrong rating allowed the green wire to burn through along its entire length from the left rear light to the bulbholder.
Along the length of the run of the harness the green wire melted into the heavy black wire (with a 30A fuse rating) of the HRW and the damage was compounded.
A new license plate lamp holder and a wiring harness from the left rear light to the lamp is now needed.
Sourced locally.
Just goes to show that brute force is no use and that all fuses should be of the right rating. Could have been worse in all that fibreglass and wiring.
Thanks to all those who replied.