No Dash Board/ Instrument lights any ideas

C

casper171072

New Member
Hi everyone, I have a 72 P6 V8 S2, what I dont have is any interior dashboard/instrument illumination at night. All the lights work on the exterior of the car, and the interior dome light works on its switch but I have no lights on the instruments or switches or the auto box selector. I know there is a fuse which I have checked, this seams ok but will get another and replace it anyway, other than that where should I look. I have also checked the dimmer switch (though I have no manual for the car I assume it is on the left side of the instrument pod), please correct me if Im wrong and its really that simple, and Im realy that thick :)
 
Hi,

I'd start with the fuse first then check the dimmer.



13 = Instrument Panel Lighting
14 = Switch Panel Lighting
35 = Gear Selector Illumination

which are all fed via 8 amp Fuse 32 (= 9/10 in the fusebox). This in turn takes its feed from the live side of 5 amp Fuse 41 (= 7/8 in the fusebox) which protects the LH side and tail lights + number plate illumination.

40 = Main Lighting Switch

Good Luck!
 

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Hi Casper,

Try the simple things first, although you probably have done so already...

The dimmer knob gradually increases the brightness BUT then the light goes off when turned to its full extent! First check this by twisting the dimmer knob with the side lights on!
 
Ok, its not the fuse, and its not the dimmer, I have twiddled every knob to check. As I havnt got the owners manual with the car can someone confirm which one is the dimmer switch. I think its time to go in! check for wires adrift etc. if anyone has any other ideas let me know.
 
There are 2 knobs on the left hand side of the instruments - one does the trip reset & the other does the panel lights. I can't remember which way round they are.
 
Phil Robson said:
There are 2 knobs on the left hand side of the instruments - one does the trip reset & the other does the panel lights. I can't remember which way round they are.
Click to expand...

On my car the top knob is the trip reset.

If it's not the fuse or the dimmer it could be something as basic as all the bulbs being blown. When was the last time all of the lighting worked? Alternatively it could be a bad earth. I'm not sure if they all earth through the same point but it's worth checking. IIRC The earth for the instrument lighting on my car is on the drivers side bulkhead next to the indicator relay. Certainly worth a look if all the lights stopped working at the same time.

Finally, a check of all connectors on the instrument panel and switch panel might reveal a poor connection somewhere. As part of the diagnosis process I'd take all the connectors off one at a time and give the contacts a good clean with a fibre glass pen. It's amazing how dirty they get over time and bad connections can cause real headaches when diagnosing electrical faults.

Good luck I hope you get it sorted.

Dave
 
just had same issue and found it was the dimmer switch itself that was goosed.

took clocks out and dimmer has 2 red wires which connect in the bulkhead - the dimmer itself has 2 spade connectors that connect to dash.
fortunatley had a spare dimmer replaced it and clocks all light up fine.

it solved issue for me but yours may be a diferent problem.

if you dont have a spare dimmer to check
I should think you could remove dimmer and wire it through a 12 v to a bulb to check it dims out of unit
at least this would isolate 1 possible problem

good luck
 
Had a similar problem recently in my 2000SC (strip speedo). My one turned out to be a short circuit in the back of the light for the clock(time). Wiggled the wires and the lights came back on fine and then sorted the connections properly, been fine since. Good luck.
 
As a few people have mentioned it could be something really simple. Mine did the same just before the MOT earlier this year and I tried loads of things but in the end it was dirty terminals in the fuse box. So, although the fuse was good there was still no connection.
 
Ive had the dash out today and found that it may be the dimmer. Found there are two red wires that come out of the dimmer and connect to a metal plate that has what I can describe as like a circuit board on it. Any one know what this is, one of the tracks on what i guess is an early circuit board has snapped. This plate in itself is just screwed to the vertical in the centre of the dash that holds the clocks in. So whot is this and what is it for. Thanks again.
 
Here is a picture of what I was trying to describe. Think this is the reason my dash and switch lights dont work
 

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Its a resistive element and it is open circuit (faulty) its function is to drop to drop the voltage, easiest fix is to replace it or you could try and join the 2 ends that have parted company by soldering or silver soldering the ends together with the help of a peice of bridging wire, Depending on the metal used in the resistive element it may not solder with conventional solders hence my suggestion of silver solder or possibly sil-fos.

Graeme
 
I took the dimmer switch out today and joined the two connections on the back of the instrument panel where it fits, I was hoping this would bypass the dimmer and get the panel lights working but this has not happened. Any ideas, is joining the two connections from the dimmer correct to bypass it? I can live without the dimmer if I can just get the panel lights
 
Hi, have you got 12v at one of the wires? If no trace back to light switch.
If yes trace forward to bulbs.
 
I NOW HAVE LIGHTS!!!!!!!!!!!! :D thanks for everyones help. It was the resistive element that I photographs got a replacement from the everso helpful chap at Rover spares in Retford Doncaster
 
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