Fog light (again)
Fog light (again)
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Discussion

33sport

Original Poster:

50 posts

49 months

Sunday 12th September 2021
quotequote all
Hi all
I posted a month back on this subject.
Rear fog light not working.

I have tried with dip beam on and off.
The bulb was changed to a known working one.
The ribbon to the control box I swapped over with the hazard one which again I know works, also plugged in the hazards to the fog light switch to check and it switches the hazards on so it works.
With the advice of a person on here, I have checked to see if there’s a live feed to the control box (red/blue + & yellow-) all good.?
Fuses all checked and ok
All other lights works to the rear of my car.
Really stuck in this, so do need help/advice please.
Many thanks.

Sir Paolo

244 posts

85 months

Sunday 12th September 2021
quotequote all
Hi, if the fault is proving elusive, and defying logic (as electrical ones are apt at doing), it could be worth getting an auto electrician to have a look.

For the sake of around £45.00, he should be able to diagnose the problem fairly quickly and save you a lot of head-scratching.

Good luck!

Belle427

10,845 posts

250 months

Sunday 12th September 2021
quotequote all
Did you also test at pin B5 on the module which is your 12 volts out to the fog lamp, yellow/red cable?
If you have 12 volts here your fault lies somewhere in the wiring from here to the lamp.

33sport

Original Poster:

50 posts

49 months

Sunday 12th September 2021
quotequote all
Hi yes did test across yellow/red and showed 12v.
Was wondering which side of the car the loom runs.?
Guessing near side?

Belle427

10,845 posts

250 months

Sunday 12th September 2021
quotequote all
I can’t answer that sorry, maybe Steve D will be along soon as he has in depth knowledge of the wiring.
May be a poor connector somewhere as the loom seems to use a few of them in other circuits.

nawarne

3,128 posts

277 months

Monday 13th September 2021
quotequote all
Remembering from chasing rear light problems from when I had a Chimaera, I recall being directed to multi-pin connectors found behind the removable cover at the B post.

Toothbrush and contact cleaner on the male/female pins soon restored illumination. Think there's connectors on both sides.

Nick.

33sport

Original Poster:

50 posts

49 months

Monday 13th September 2021
quotequote all
Hi I have checked the connections in both B pillars, the main rear lights etc is on the near side. Again checked for corrosion all ok, but there’s no voltage on the red/yellow fog light wire?
I’m guessing there’s a fault further forward around the fuse box and cabling.?
Anyone now if there’s another connector around the fuse box area, or separate fuse/ relay.
Thanks for the help so far.

Belle427

10,845 posts

250 months

Tuesday 14th September 2021
quotequote all
From some pretty accurate diagrams I have it goes straight from the control module back to the fog light.
Not much help I know but connectors are not shown on them.
It’s a pita but maybe try and trace it down from the module, there is no easy route really to just run a new cable unless you go under carpets which is a bit of a botch.

Edited by Belle427 on Tuesday 14th September 07:55

Steve_D

13,799 posts

275 months

Tuesday 14th September 2021
quotequote all
The fog lights will only work with dip beam. Does the Fog switch light up?
Yellow/Red goes from lights module, across the glove box, nearside door cill, up the B pillar where there is a connector, over wheel arch into boot.
If there is no +12 at the B pillar connector (leave it connected and measure in the back of each connector half) then the problem is further forwards.
There is a black connector in the A pillar/glovebox area with a yellow/red wire but that is not it. I dont believe there is a connector for this wire in the A area.

Steve

33sport

Original Poster:

50 posts

49 months

Tuesday 14th September 2021
quotequote all
Hi Steve
I have no power on the yellow/red wire at the b pillar connector.
I have 12volt power on the yellow/red cable in the control box behind the radio area. ?
You say there’s no other connections from the b pillar back to the control unit, then I’m assuming I have a broken cable.?

Steve_D

13,799 posts

275 months

Tuesday 14th September 2021
quotequote all
I have this nagging thought that there is a connector behind the carpet at the A pillar but I can't find anything in my notes of when I traced the whole loom.
May be worth pulling the carpet back and looking as you will have to dive in there to run a new wire.
Also when you find the loom at the A pillar and find the wire you can stick a pin into it and see if you have +12 that far.

Steve

33sport

Original Poster:

50 posts

49 months

Tuesday 14th September 2021
quotequote all
Hi Steve
I have just checked the control box and there is no power on the yellow/red wire but there is 12volt on the blue wire?
Does this sound like the control box is shot?

Steve_D

13,799 posts

275 months

Tuesday 14th September 2021
quotequote all
33sport said:
Hi Steve
I have just checked the control box and there is no power on the yellow/red wire but there is 12volt on the blue wire?
Does this sound like the control box is shot?
The blue (pin A2) is 'headlights on' so should be +12.
You should also have +12 at pins:-
A4 - Permanent +12 supply
A1 - Dip beam headlights
A3 - Side lights
B3 - Dash illumination
and of course B5 your yellow/red for the fogs.

Is the ring lit around the fog switch saying they are on?
If not then we may be getting back to the question I asked on the earlier thread as to the possibility you have fitted one end of the ribbon cable the wrong way round.

Steve

33sport

Original Poster:

50 posts

49 months

Tuesday 14th September 2021
quotequote all
Hi Steve
I’m not sure of the correct layout on the white connector, is there a diagram showing this?
I’m pretty sure I’ve checked the ribbon cables being the wrong way round correctly, but will check again.!
Finally the control box was making a fast clicking noise earlier, so I turned off the ignition then back on and the clicking stopped??

Steve_D

13,799 posts

275 months

Tuesday 14th September 2021
quotequote all
Does the fog switch light up?

Try this.



Do you have my wiring diagrams?
If not then PM me.

Steve

33sport

Original Poster:

50 posts

49 months

Tuesday 14th September 2021
quotequote all
Hi steve thanks for the diagram will look tomorrow.
Also the fog light switch does not illuminate.?

Steve_D

13,799 posts

275 months

Tuesday 14th September 2021
quotequote all
33sport said:
Hi steve thanks for the diagram will look tomorrow.
Also the fog light switch does not illuminate.?
My money is on the ribbon cable.
ribbon has 5 lines but only 1, 3, 5 are used.
1 is earth
3 is for the switch to earth the fog relay coil in the module
5 is output from the fog relay to illuminate the switch

So if you flip the ribbon over nothing happens but better still no damage is done.

Steve

33sport

Original Poster:

50 posts

49 months

Wednesday 15th September 2021
quotequote all
Hi Steve
I have swapped the ribbon cables over and still no power to the red/yellow cable B5, although B5 shows a small outage of 0.175v when the main lights are on dip.?
Not sure where to go from here, is there some who you could recommend who can check the control box?.
Regards
Stuart

33sport

Original Poster:

50 posts

49 months

Thursday 16th September 2021
quotequote all
Hi Steve
I have swapped the ribbon cables over and still no power to the red/yellow cable B5, although B5 shows a small outage of 0.175v when the main lights are on dip.?
Not sure where to go from here, is there some who you could recommend who can check the control box?.
Regards
Stuart

Steve_D

13,799 posts

275 months

Thursday 16th September 2021
quotequote all
You still need to report back to me on the voltage checks I asked you to do last tuesday.

No point thinking about testing the module until we know it has all the supplies it needs.

Steve