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Fog Light Conversions for beginners


Pixelfill

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  • 1 month later...
  • 2 weeks later...

I have a slight variation on the theme of this fog light conversion ... (I think everyone has their own):

 

  • it still uses two relays (of the changeover variety = 5 pin rather than 4 pin);
  • it uses the OEM bulb failure light as the tell-tale to indicate your fog lights are on (otherwise this works as standard) so you don't need an illuminated switch;
  • it doesn't require any resistors which is the main reason I put some effort into coming up with this variation.

Please see picture attached (with thanks to Pete Betts whose diagram I used as a template). N.B. The relay pins are correctly numbered but they might not match the layout of the pins on your relays.

 

Let me know if you need more details of how this works.

Fog light.jpg

Edited by spartan
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  • 2 weeks later...
  • 1 month later...

Mike,

 

Help please!

 

Wired up my lights and relay kit as described (?) and got the following unexpected results:

 

Side lights only: All four bright red

Sides & foglights switched on: All four bright red

Foglights switched on: Nothing!!!!

Brackes only: All four bright red

Foglights and brakes on: Outer two bright red!!!

Foglights, Brakes and sidelights all on: TWo Outer lights bright red, two inners dim red

 

I checked the relay wiring. Twice. Seems correct. I only touched the two inner bulbs and their looms. Checked the relays. They are the 12v type. I am a bit suspicious of the switch but checked that pins 85, 86 do have 12v when it's on.

 

What's gone wrong???

 

Cheers

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Mike,

 

Update:

 

Checked all lightbulb wiring. Correct as in your descriptions. Findings:

 

Sidelights only = All four lights dim (5w)

Sidelights and Fogs = Both nearside lights = dim (5w) but only the offside outer one = dim (5w). The offside inner = Off!

Brakes only = All four lights bright (21w)

Brakes and sides = All four lights bright (21w)

Brakes and Fogs = The two outers = Bright (21w). Nearside inner = Dim (5w). Offside inner = Off!!

 

I checked some relay voltages:

 

Fogs switch Off = pins 85 and 86 = 0v

Fogs On = pins are at 12v

 

Any suggestions as to what to check next? It's possible one (or both) of the relays are faulty?

 

Cheers

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You will notice from the diagram that the output wires to both tail lights and brake lights have been joined together (the exisiting connections from the loom are left disconnected on one side). It should be impossible, therefore, for either nearside tailights or brake lights to behave differently to the offside. From your description, they do behave differently and ipso facto the wiring can not be the same as the diagram ...

 

Maybe some pictures of your wiring would help?

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Here's a few I took yesterday...

 

A bit difficult to describe, or follow, but the first two show the nearside and offside light connections. The one with two connections is the nearside.

Next two are views of the Relay 1 (with the ballast resistors)

Next one is a view of Relay 2 with the piggybacked connections. Last one is a view of Relay 1 again...

 

I have followed the wiring through the bulkhead. It is correct. But as you say, why should the offside inner behave differently from the nearside? Can you provide expected voltage readings for each relay connector? It could help diagnosis.

 

Cheers.

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Rofl@tags

:confused: please explain

 

Here's a few I took yesterday...

 

A bit difficult to describe, or follow, but the first two show the nearside and offside light connections. The one with two connections is the nearside.

Next two are views of the Relay 1 (with the ballast resistors)

Next one is a view of Relay 2 with the piggybacked connections. Last one is a view of Relay 1 again...

 

I have followed the wiring through the bulkhead. It is correct. But as you say, why should the offside inner behave differently from the nearside? Can you provide expected voltage readings for each relay connector? It could help diagnosis.

 

Cheers.

 

I've been tearing the garage apart looking for my multimeter to try and work it out, sorry I couldn't find it.

 

Mike

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OK - so maybe some pictures of your wiring won't help after all. ;)

 

Going back to what you describe in your 'symptoms', I think I have an explanation:

 

  1. the loom side of your brake lights is connected to pin 87a of relay 1 (rather than pin 30)
  2. the light side of your brake lights is connected to pin 30 of relay 1 (rather than pin 87a)
  3. the light side of your nearside inner tail light is not connected to pin 87a of relay 2 (I think it may be connected to pin 30)

The first two are easily fixed: you just need to swap over the connections at the relay, one for the other. The third will need some careful tracing.

 

Of course, it could also be that (as you've already suggested) that one of the relays isn't working properly or maybe someone's tinkered with this wiring before you got there ... :)

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Hey - you were right on the money !!

Tried 1 & 2 - no change.

 

Then tried 3. I did trace back the wire and sure enough I'd connected the nearside inner light to pin 30 of relay 2! A quick swap over and - Success!!!:D:D:D

 

A very neat foglight conversion - and I have finished it off with a neat rocker switch which has a red LED telltale fitting into the active spoiler switch hole.

 

Many thanks;)

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Glenn glad to see you've sorted it, I'm sorry I wasn't able to help you further, I've been a bit busy recently, thanks Spartan for your help.

 

If it's okay with you both I'll prune this thread back a bit to make it a bit more readable and to include your problem with it's resolution.

 

Mike

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Glenn glad to see you've sorted it, I'm sorry I wasn't able to help you further, I've been a bit busy recently, thanks Spartan for your help.

 

If it's okay with you both I'll prune this thread back a bit to make it a bit more readable and to include your problem with it's resolution.

 

Mike

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