Odd tail lights problem!?

[Scottd]

Both tail lights and number plate lights aren't working. Bulbs seem fine and break lights are working. For a while just the passenger side tail light was out.

The break lights stopped working for a while but they seem fine now - fixed themselves

Am worried there's summin up with the lectrix One of the wires near the fuse box was rubbing on the chassis and doesn't look too healthy. I put some foam around it but it doesn't seem to have helped much.

cheers

scott

[BiggestNizzy]

have you checked it with a multimeter ?

[Scottd]

have you checked it with a multimeter ?

say again?


/goes to google

[BiggestNizzy]

one of these
Multimeter

If you know an electrician they will have one it's good for checking voltage/ continuity and that one is really cheap.

But I suppose you will need to know how to use it .

[Scottd]

.....But I suppose you will need to know how to use it .

There is that I have a home made thingy that makes clicking noises to tell you if there's any breaks in the wire. I guess it's a fancy one of those??

[BiggestNizzy]

yea it's one of those with nob's on

[Chopperver1]

Taking an educated guess, sounds like you have an earthing problem.

I don't have acccess to the workshop manual right now but if I remember I'll have a look at mine tonight to see if there is a common earth point for the rear lights and give you a shout back.

You could have a look yourself.

Head inside the boot, upsidedown, look backwards at the lights. (assumes you don't have a boot bag) Do the ends of the cables at the lights in question or the actual bulb holders (take the bulbs out and look at the contacts in the holder) look a bit fusty ? - white deposits

If so then take them off and a quick rub with a bit of fine wet and dry paper, reconnect. You'll probaby have to clean each one. If it works then put some vaseline on the connectors (not the bulb holders) to stop the corrosion returning. If your rear clam engine gutter drain pipe is blocked then you'll get a bit of damp in there which will cause this over time.

[robin]

If you have some silicone grease that would be better than vaseline, but vaseline obviously works (and has for years ).

Do the front side lights work when you turn on the lights?

If the answer is yes then the problem is in the harness or lights/earthing at the rear. If the answer is no we'll chase elsewhere.

Check connectors on bulbs as suggested above.

If you have a boot bag car then remove the boot bag on the near side and you should see the ECU bolted to a metal plate. There are also a bunch of connectors clipped onto the same panel - the last one of these (nearest the back of the car) is the RHC (Rear Harness Connector); pins 4 and 8 are the live feeds for the bulbs from the front; all the black wires are the earth connections for the rear. You can see the RHC in this picture:



They all run to a common earth at the earth post which is bolted through the front end of the plate the ECU is mounted to. It's called the Engine Management -ve binding post in this picture:



Cheers,
Robin

[Scottd]

Cheers for this guys, I'm gonna go through all these things tomorrow at lunch (weather permitting ).

Earthing thing is something I'll def check. I've heard that's the problem behind my alarm fobs having a range of about 10cm from the receiver. But I've never worked out where the earths were because I've never noticed that page in the manual before so I'll go through all of those.

Rear light connectors seemed fine but will double check tomorrow.
Side lights aren't on when main lights are on. One side light bulb connector is blue with foostyness. Will try and rub down an stick a bit of white grease on it (would have done so before had I known, cause the back of the headlights seem to get hit with water)

thx again!


scott

[robin]

Scott, spotted on another thread your car is a 99 - the layout of the later S1 is different with the ECU and I suspect most of the gubbins that was on the ECU plate being in the engine bay rather than the boot. I think the RHC is still in the boot, though, clipped to the clam rather than a metal plate.

But if the front side lights are working no better than the rear side lights I doubt the problem is there.

When you turn on the ignition, no lights on, there should be a dim glow from the side light switch (half strength bulb). Is this there?

When you turn on side lights only (no head lights), the dim glow should become brighter. Does this happen?

Also when the side lights are on, the instruments should be backlit, the red ring around the cigarette lighter should light up and the radio (if fitted) should go into night display mode. Does this happen?

If you have a test light (you know, like a screwdriver but with a bulb in the handle and an earth lead on a croc clip) or a multimeter you can measure the voltage at both sides of fuses 16 & 17 (LH and RH respectively). When the lights are on you should see +12 on both sides of both fuses.

To test the circuits, you can identify fuse 16 & 17. Using a piece of wire, touch from fuse 2 to fuse 16 or 17 (you should be able to see the little metal spades protruding out the top of the fuse). This bypasses the switch and feeds current directly to the bulbs.

Cheers,
Robin

[Scottd]

OK I found the rear earth, it's about the dirtiest thing in the whole engine bay. As I gave it a quick clean I noticed the bracket the earth bolt is connected to isn't very secure. With just a bit of WD40 one of the rear tail light has flickered into action. Tonight I'll give everything a good clean and see if I can check that bracket out. If it's like any of the other original bolts it'll be practially rusted through.

When you turn on the ignition, no lights on, there should be a dim glow from the side light switch (half strength bulb). Is this there?

Think so

When you turn on side lights only (no head lights), the dim glow should become brighter. Does this happen?

Yup. It's not the greatest working swithc tho, normally takes a couple of presses to make it stay in (and light up)

Also when the side lights are on, the instruments should be backlit, the red ring around the cigarette lighter should light up and the radio (if fitted) should go into night display mode. Does this happen?

Yup

If you have a test light (you know, like a screwdriver but with a bulb in the handle and an earth lead on a croc clip) or a multimeter you can measure the voltage at both sides of fuses 16 & 17 (LH and RH respectively). When the lights are on you should see +12 on both sides of both fuses.

Will add it to my things to check tonight.

To test the circuits, you can identify fuse 16 & 17. Using a piece of wire, touch from fuse 2 to fuse 16 or 17 (you should be able to see the little metal spades protruding out the top of the fuse). This bypasses the switch and feeds current directly to the bulbs.

This sounds like you're trying to kill me and will be the last thing I try

cheers

[robin]

Hmm - if all the "does X happen when Y" tests worked I am surprised that you have no side lights front or rear - sounds like a bit of an earthing and corroded connector fest ...

Cheers,
Robin

[Scottd]

Thanks to some sunshine I managed to spot just a tiny bit of corrosion on one side of two fuse connector inside the fuse box. The two fuse connectors for the left and right rear lights!

Break lights then decided now to stop working! Quick adjustment of the pedal sensor (once I found it! So glad I printed off all the manual at work a couple of year backs, only a couple of thousand pages heh) so they're now sorted too.

One thing, I take it that the "-ve binding post" is the opposite of an earth?? I was about to take a wire from the end of the bolt to a part of the chassis to see if that would help earth it. Then I noticed the bolt went into a plastic bush. So it was at that point I decided to check the fuses one last time.

So lights fixed in about 20 mins, a record for me* but at least I know where the 'earths' are now

*or it would of been, but I decided to re-adjust the bonnet catch as I'd put a spacer in to lift the front of it (it had sat low and was catching the front clam since I got it back from JMG paintshop a year ago). Took me about 2 hours and 10 times of it being stuck shut - followed by some heart stopping shaking of bonnet to get it free again. It's still not perfect, closer tho Now I know the kind if tolerances NASA must be used to half a mil either way! Wot a cnt of a job!! That'll teach me to polish it, oily hand prints all over the front clam!!

But hey, at least I can drive at night again!!


Thx again!!

[Scottd]

Oh, and the front earth, next to the battery I have looked for that loads of times but finally found it thanks to your manual page. Hmmm, maybe I didn't spot it before because, neither is it visible, nor reachable by any tool known to man, without (probably) unbonding half the fekin chassis!

[robin]

-ve binding post and earth are the same thing.

Glad you got it sorted!

Cheers,
Robin