Fog & reversing lights ( & more things dying left right and centre)

Topic: Fog & reversing lights ( & more things dying left right and centre) (Read 3710 times) previous topic - next topic

Fog & reversing lights ( & more things dying left right and centre)

April 18, 2022, 04:37:06 PM

Please excuse if this is a bit long but I'm going a little insane here. Car is a 1991 8V GTI. The fuse box diagram in Haynes has proved unhelpful.

First noticed no power to the central locking motor.
Whilst testing stuff at the rear of the car, realised I had no reversing lights or fog lights.

Fuses on the fuse box are fine.
Removed the light clusters and tested them off a battery, they are fine. Bulbs fine.
Fog light switch on the dash seems to have no power to it at all.
Did some reading and thought it could be the relays. Swapped the 53 relays in spaces 10&11 in case one was a dud - no difference. Tested both 53 relays with a battery & for continuity - they're fine so not both duds.
Tried putting a 53 relay in space 7 as per some people online & Haynes - no difference.
At this point I realised the wipers no longer worked - they did before I started messing

Any suggestions would be very much appreciated, I'm a bit alarmed by the loss of the wipers in case I've managed to screw something else electrical up in the process!

As for the central locking... it's now somewhat lower down in my priorities...

Thanks in advance

Re: Fog & reversing lights ( & more things dying left right and centre)

Reply #1 – April 19, 2022, 09:22:48 AM

Hello!

Sounds like you've got some odd things going on there.
The Haynes manual isn't the easiest to follow.

I've found this site awesome for wiring...
http://www.a2resource.com/electrical/CE2.html

Might be an idea to pop the fuesbox down and start testing from the back of it.

Re: Fog & reversing lights ( & more things dying left right and centre)

Reply #2 – April 19, 2022, 11:09:48 AM

Quote from: Monkey on April 19, 2022, 09:22:48 AM

Hello!

Sounds like you've got some odd things going on there.
The Haynes manual isn't the easiest to follow.

I've found this site awesome for wiring...
http://www.a2resource.com/electrical/CE2.html

Might be an idea to pop the fuesbox down and start testing from the back of it.

Haha yes it's def odd. Thanks for the link!

Re: Fog & reversing lights ( & more things dying left right and centre)

Reply #3 – April 19, 2022, 01:05:54 PM

Don't want to panic you but the fuse box sits directly below a known water leak area. If you are unlucky and your fusebox has had water damage it can cause all sorts of havoc. But even worse case scenario isn't really a big deal. You can pick up a replacement easy enough and it's not a big deal to swap over. Good luck, please keep us updated

Re: Fog & reversing lights ( & more things dying left right and centre)

Reply #4 – April 19, 2022, 03:08:34 PM

Quote from: Eddypeck on April 19, 2022, 01:05:54 PM

Don't want to panic you but the fuse box sits directly below a known water leak area. If you are unlucky and your fusebox has had water damage it can cause all sorts of havoc. But even worse case scenario isn't really a big deal. You can pick up a replacement easy enough and it's not a big deal to swap over. Good luck, please keep us updated

Ah, thanks for the heads up! I don't think water is getting in, but I'll double check.

Someone also suggested a bad earth so got a couple things to explore.

Re: Fog & reversing lights ( & more things dying left right and centre)

Reply #5 – April 19, 2022, 07:56:10 PM

the plot thickens, going to write everything in one place so i don't completely lose it, please no-one feel obliged to read this unless you're feeling especially heroic lol.

dash switch
got worried that when i tested power to the switch, maybe the sidelights weren't on, so did it again
so tested it with sidelights - nothing
main beams - 9V
went back to sidelights - now we have 9v (

?)

okay so if there's 9v sometimes, figured maybe the switch IS (part of) the problem
tested the switch in the other car, it never lights up, so swapped it for one which does
sadly this did absolutely nothing to fix the problem

water
Good news - I can't find any evidence of water getting in, but then I guess it doesn't take much and it's been a dry few days.

earth
there is a connection to the bodywork just to the right of and above the fusebox, which i assume is the earth - this seems fine at the bodywork end.

so now i am going to learn all about the back of the fuse box in case something is wrong there. according to the CE2 diagram from Monkey both fogs and "back up" lights (reversing lights?) come from "K" so i might start there, although some of the "K" stuff def works so not overly hopeful haha.

Re: Fog & reversing lights ( & more things dying left right and centre)

Reply #6 – April 20, 2022, 04:30:38 PM

Good luck, and if dry that's a bonus.

Re: Fog & reversing lights ( & more things dying left right and centre)

Reply #7 – April 21, 2022, 08:32:04 PM

Today's updates, lol:
- went through every connection on rear of fuse box making sure nothing loose (nothing was, and this changed nothing)
- tested the reverse switch on the gearbox itself, if i bypass this my reversing lights are back!! so ordered a new one and hopefully that part of the problem will be solved

- tried a spare headlamp switch as apparently on the t25s if thats faulty it can mess with fogs, sadly no joy still

Re: Fog & reversing lights ( & more things dying left right and centre)

Reply #8 – April 22, 2022, 09:02:34 AM

You may want to inspect the wiring that runs between the headlight switch and the fusebox.
They are known to burn the earth lead out of them.
This is usually if the wrong switch is fitted, though sometimes they do it for fun too!

Re: Fog & reversing lights ( & more things dying left right and centre)

Reply #9 – April 22, 2022, 05:01:19 PM

So the descent into madness continues...
Decided to compare every voltage at the switch with my other golf, to try and work out where the fault is
Both cars are 1991 CE2 fusebox

The numbers 1-5 refer to the connections on the back of the fog switch, pic for ref below

# - colour - function for each connection:
1 - brown/white - unknown
2 - grey - unknown
3 - yellow/white - power to front fogs
4 - grey/white - power to rear fogs
5 - grey/yellow - power to relay on fusebox *according to a bloke on fb

On the left is the working car (although it only has rear fogs); on the right is the GTI with the problems

I'm ignoring anything that connects to 3 at the moment cos its front fogs (the working car doesn't have them), but otherwise there are some definite differences - whether off or on, the GTI has some voltages that i suspect shouldnt be there (connection between 2-5, circled in pink) and then when the headlights are on, the GTI is lacking some voltages (1-5 and 4-5 circled blue bottom right)

(side note - is anyone ready to stage an intervention for me yet?? my partner came out to "make sure i was ok")

er now my knowledge of electricals is poor but i'm thinking maybe i need to trace wires #2, #4 and #5 back towards the fusebox, i've got a fortnight of exams now but once they're done i've recruited a mate who understands electrics better than me to come look with me, so maybe he can work out what my "hElP tHe nUmBeRs ArE dIfFeReNt" means

Re: Fog & reversing lights ( & more things dying left right and centre)

Reply #10 – April 25, 2022, 03:24:36 PM

FYI, brown throughout the whole car is Negative/Ground or Earth. This is easy to remember if you think as Earth as brown... as in Mud ... earth, get it?

So I suggest your Brown/white combo is an Earth of some description.
The switch should illuminate with the dash lights, I suspect that's the grey wire (Dash illumination is usually blue/white but I'm sure in some instances there's also a grey).

Auto electrics are my weak point too, I'm happy with a bag of spanners but electrics do my head in.

I have a multi-meter now but for years I didn't bother. Instead, I use/used a small bulb as a test bulb.
A mk2 sidelight bulb and holder are perfect as there's two spade connectors built in...

Run a couple of wires off this, you can put a terminal connector on the end, a crocodile clip or whatever... or just leave as bare wire.

So, if you earth one end, a good earth is always the screw for the interior light switch located in the door shut, since I find I often work with the door open anyway. If you've left the end bare wire you can unscrew a bit, wrap the wire round and screw back up... this is proper hillbilly, but works.

Now you can poke your other end in places and see when your light bulb illuminates.

i.e. poke the other end into terminal 2, does your bulb light up? no, switch on the headlights, does it illuminate now.... yes. This is your dash illumination.

Hope that helps.

Other people may say get a multimeter and don't test electrics in this way.... but it's what I've always done to help me find out when a wire has power or not.

Re: Fog & reversing lights ( & more things dying left right and centre)

Reply #11 – April 27, 2022, 04:28:32 PM

Quote from: Eddypeck on April 25, 2022, 03:24:36 PM

FYI, brown throughout the whole car is Negative/Ground or Earth. This is easy to remember if you think as Earth as brown... as in Mud ... earth, get it?

So I suggest your Brown/white combo is an Earth of some description.
The switch should illuminate with the dash lights, I suspect that's the grey wire (Dash illumination is usually blue/white but I'm sure in some instances there's also a grey).

Auto electrics are my weak point too, I'm happy with a bag of spanners but electrics do my head in.

I have a multi-meter now but for years I didn't bother. Instead, I use/used a small bulb as a test bulb.
A mk2 sidelight bulb and holder are perfect as there's two spade connectors built in...

Run a couple of wires off this, you can put a terminal connector on the end, a crocodile clip or whatever... or just leave as bare wire.

So, if you earth one end, a good earth is always the screw for the interior light switch located in the door shut, since I find I often work with the door open anyway. If you've left the end bare wire you can unscrew a bit, wrap the wire round and screw back up... this is proper hillbilly, but works.

Now you can poke your other end in places and see when your light bulb illuminates.

i.e. poke the other end into terminal 2, does your bulb light up? no, switch on the headlights, does it illuminate now.... yes. This is your dash illumination.

Hope that helps.

Other people may say get a multimeter and don't test electrics in this way.... but it's what I've always done to help me find out when a wire has power or not.

Thank you! I'll put something similar together when i get back to it - much appreciated

and for the info re wire colours!

Re: Fog & reversing lights ( & more things dying left right and centre)

Reply #12 – May 06, 2022, 07:20:20 PM

So yesterday a mate who is much better with electrics kindly looked at this while I did a nice, reassuringly simple oil and filter change for him lol. To sum it up he says "the fog lights don't know the headlights are on" - if he ran ignition live from the headlight switch into the back of the fog switch they start working. He said he'd either wire up a new switch for the fogs independent of headlights OR I could take the fusebox apart and look for a reason they weren't communicating in there.

We ran out of time anyway and given the wipers / locking / washers not working either I thought better have a look in the fuse box and sure enough when I opened it today there was some minor corrosion but more worryingly, a small piece of it just .... fell out

Fiddling about the broken piece is one of the prongs of where relay #4 plugs in.

I wasn't totally convinced by this because surely by wiggling #4 it can touch one prong and you'd think that was enough, however, having put the whole thing back together and wiggled #4 NOPE NO FOG LIGHTS so looks like I'm off to ebay for a new fusebox (as Eddypeck said, plenty on ebay - which is good because from VW it's £600?!!!)

Will update once I've tried another fusebox

Re: Fog & reversing lights ( & more things dying left right and centre)

Reply #13 – May 15, 2022, 11:56:59 AM

Happy update at last - new fusebox solved the problem

Re: Fog & reversing lights ( & more things dying left right and centre)

Reply #14 – May 16, 2022, 08:10:47 AM

Happy Days! I was wondering about this one.