Project BX - no dash lights

Post by **Jon** » 04 Oct 2004, 02:09

Didn't do a lot today due to rain, then family commitments. Cleaned my tools and garage and junked all the trash rusty bits.
Anyway, upon moving the car tonight, found that I had no dash lights, heater backlights etc. (When I drove the car home they were working, I was amazed at the time!) According to the handbook, they run off fuse3-25A, which also controls brake lamps, wash wipe, front electric windows etc, all of which still work. I pulled the cigar lighter out as I remembered that the + side is a joining point for 3 cables that do cigar lighter illumination, heater backlights etc. There was no power at all with ign on when I tested with multimeter. I also fiddled with the rheostat under the dash, nothing. Dash as black as your hat. [V][:(]
A bit perplexed, could the rheostat have just failed for no apparent reason? Its too dark now to investigate but assume that I could pull the 2 wires off it and bridge them. If it still doesn't work after this, I don't know what to do.
Any suggestions gratefully received!

prm · Post by **prm** » 04 Oct 2004, 03:59

Jon
Bridging out rheostat should give you and indication if unit is faulty. Never known one to give any problems though.
Have you just fitted your radio flap ??. Multipin circuit connectors maybe above radio slot.
With your chassis repairs you may like to fit a mod to sunroof drains, front and rear whilst welding in new plates. Extending plastic tubes to outside bodywork by drilling clearance/exit holes in rear cross-member box section and front part of sills which also helps to drain any water build-up.
R
Peter

Post by **Jon** » 04 Oct 2004, 04:13

Thanks for that Peter.
Whilst I have not fitted a new radio, I did pull through the existing connectors to have a look at them with a view to making good when fitting new radio, I'll take a look tomorrow and see if I can locate that multipin, plus of course bridge the rheostat if thats not the problem.
I'll also whip out the rear lamp clusters and locate the sunroof drain tubes, certainly I believe that they are too short and have been draining into the cross-member.
Welding has been more extensive than I originally planned, I hope to finish this job tomorrow evening, and primer/stonechip then wax for a neat long lasting repair.

NiSk · Post by **NiSk** » 04 Oct 2004, 12:19

The rheostat sits in a bit of bent aluminium (supposed to act as a heatsink probably). The contacts often get graunchy - first check that there still is something for the wiper blade to connect with, if so spray with contact cleaner. You may have to retension the wiper blade (or replace the whole thing!)
//NiSk

wrinklet1 · Post by **wrinklet1** » 04 Oct 2004, 13:29

I have known the rheostat to burn out on a BX, Depending on where its burnt out a dab of solder may well do the job for you
Paul

oilyspanner · Post by **oilyspanner** » 04 Oct 2004, 14:32

I have replaced the rheostat before too
Stewart

DLM · Post by **DLM** » 04 Oct 2004, 15:35

I've had a dead rheostat too - bridging it out is the first thing I'd recommend in the circumstances you describe. If I remember correctly there is also a contact behind the cigar lighter which can kill the dash lights if it's displaced.

clivetheitman · Post by **clivetheitman** » 04 Oct 2004, 16:23

Jon I have the same problem on my new to me BX estate that I am in the proccess of bringing back up to road use spec. if you track this fault down before I do can you please post the fix. I am thinking of mounting a small set of leds or lamps in a shrouded cover to iluminate the dials on the instrument panel from the front as I do not want to take the instrument console off and bust something. all warning light and headlamp lights are working only the dial lights and the light on the rear screen rear windscreen washer hazard switch and rear spot lamp plus heater controls ect are not lighting up when ignition is on, but the 4 switch lamps do come on when in use.

AndersDK · Post by **AndersDK** » 04 Oct 2004, 19:29

Clive -
It could be Fuse F3 (25A) which feeds all the backlighting and lots of other circuits like the rear stop lights.

oilyspanner · Post by **oilyspanner** » 04 Oct 2004, 22:35

These might ba an answer to the dash bulb problem, only what colour to choose.....
http://www.digimemcards.co.uk/html/dash ... bulbs.html
Stewart

clivetheitman · Post by **clivetheitman** » 05 Oct 2004, 00:06

Anders the fuse is ok, but power has disapeared along the wiring feed somewhere between the fuse and the dashboard lights ect. no 12v supply to the dimmer resister so suspect a failed wire or connection somewhere.[:(]

NiSk · Post by **NiSk** » 05 Oct 2004, 00:15

Reply with Quote
These might ba an answer to the dash bulb problem, only what colour to choose.....
http://www.digimemcards.co.uk/html/dash ... bulbs.html
Stewart
Actually thats not such a daft idea - (appart from the silly one which changes colour!!) the only problem is that there are 21 such lamps in the XM instrumentation . . . (bank loan, anyone?)
//NiSk

oilyspanner · Post by **oilyspanner** » 05 Oct 2004, 01:00

Jon, why not find an appropriate live from the Ignition switch and splice it into the feed to the rheostat?
Stewart

AndersDK · Post by **AndersDK** » 05 Oct 2004, 03:00

Stewart has the quick solution [;)]
But Clive - we dont give up that easy - do we [8D]
In the Fuse/junction box you have a lot of different coloured multiplugs - with different pin counts and coding lugs. No 2 plugs have both same colour and same pincount. This means you may pull all plugs and always can find their correct location.
One particular plug of these - the yellow 6 pole - carry the wire feed to both the backlights rheostat and the windscreen wiper. It is pin 2 on this plug.
If the wipers are ok - then the feed to the rheostat is also ok - but the wire itself may have split on the run. It's the wire on pin 1 in the rheostat plug. You may follow it backwards.
I suspect that export RHD vehicles have extension cables/plugs in part of the harness, as found on the ignition switch cable.
These are always an extra fault possibility.

uhn113x · Post by **uhn113x** » 05 Oct 2004, 12:29

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">
These might ba an answer to the dash bulb problem, only what colour to choose.....
http://www.digimemcards.co.uk/html/dash ... bulbs.html
Stewart
Actually thats not such a daft idea - (appart from the silly one which changes colour!!) the only problem is that there are 21 such lamps in the XM instrumentation . . . (bank loan, anyone?)
//NiSk
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Agreed, considering LEDs are about 10p each, resistors ditto, and you don't need the holders as they will never need changing again. [:(]