Fog Light Switch [LED Light]

[Nathanb]

I've just upgraded my dashboard illumination bulbs to LED [white] versions, nice little upgrade!

I also replaced the light bulb in my 'Fog Light' switch on the dash, however it doesn't seemed to have worked. I've used a multimeter to confirm that I have power going to the terminal that powers the light. The actual Fog Light switch works and turns on my front fog lights [when I have my main headlights on] and also turns on my rear fog light.

One thing I did want to confirm was that I only have one rear fog light which is on the offside [Right Side]of my van,that's correct isn't it? I opened up the rear near side light and found that I had a bulb in the slot where the rear fog light bulb would be, but there was no connection underneath it. Seems to be a holder for a spare bulb, but not an actual active slot [if that makes sense?]

If my assumption i correct the does anyone have any other ideas on what I can try next to get the small light indicator to work on my fog light switch?

[CovKid]

When you say you've replaced it, with what exactly? In an application like that, its probably easiest to fit a conventional LED and resistor (cheap) to match 12v - pretty much what I've done across my entire dash. Gradually I've been utilising unused warning bulbs in the dash by replacing those too.

[Nathanb]

Hi CovKid - I replaced it with an LED upgrade bulb from Brickparts.
http://www.ebay.co.uk/itm/VW-Fog-and-Ha ... 25ac01c85a" onclick="window.open(this.href);return false;

[keytouch]

Have you tried it both ways round?

[marlinowner]

In reply to your other question, yes just one rear foglight.

[Nathanb]

@ Keytouch: For this LED bulb there is only one way to fit it, but I know what you mean as the other dash bulb LED upgrades I did had two ways to fit and only one way works.

@ Marlinowner: Thanks for confirming that there is only one rear fog light. I managed to work this out in the end by tracing the connection on the back plate of the light to the pin connector that you plug in. There is no pin connection for what would be the near side fog light. What threw me off was that there was a bulb in this slot, but presumably this is just a handy place to store a spare bulb.

Thanks for everyone's responses so far!!!

So i've tested the voltage of where the fog light LED light would go. Everything seems fine, as in when the switch is off or on the middle setting there is no voltage. Then when it's on it's third setting which is for the rear fog lights, it receives 10 volts.





Here's the LED upgrade.



I'm now stumped

[MidLifeCrisis]

Have you tested the LED ?

[Nathanb]

Yep all working fine.

[MidLifeCrisis]

Ok - so you have voltage across the two contacts that mate to the LED and you've tested the LED separately and it works - so the only thing left is that the LED isn't mating to the two contacts - with the copper strip one being the prime candidate I'd guess?!?

[bigherb]

When you checked the led did you note which way round you had the cables to make it work, the led could have been fitted the wrong way round.

[keytouch]

Did you have a working ordinary bulb in there to start with?

[Nathanb]

Thanks 'Keytouch', 'bigherb'& 'MidLifeCrisis' for your replies.

I've decided to leave it for now, jumped into my van and headed down to West Wittering on the south coast for some Kayaking. I'll get back onto this next week and give an update.

For now here are some responses.

"Did you have a working ordinary bulb in there to start with?"
You know what, I never actually tested it before I ordered the LED upgrade. I just presumed it was no longer working and as I was upgrading the rest of my original dash bulbs to LED I went ahead and ordered this one.
So when the LED didn't work as expected, I then tested the original bulb with the multimeter. I used the audible Ohm test and it worked first time. Then later on when I was retracing my original steps I tested it again and it didn't work, so was a bit confused.
When I get back I'll have another test as it will be a nice easy check to confirm that it's not the bulbs / LED but the switch connection.

When you checked the led did you note which way round you had the cables to make it work, the led could have been fitted the wrong way round.
I didn't but will check again, good point.

Ok - so you have voltage across the two contacts that mate to the LED and you've tested the LED separately and it works - so the only thing left is that the LED isn't mating to the two contacts - with the copper strip one being the prime candidate I'd guess?!?
That's what I thought, so when I used the multimeter I checked the exact spot where the LED touches the copper strip, just in case there was some corrosion stopping the flow, it was fine.
I also managed to use a micro screwdriver to push the LED connection against the copper strip once in situ, no joy.

I'll give all of these suggestions a go when I get back, so thanks once again for the help.

[keytouch]

I see you live in Twickenham, I'm just over the river in Ham. Once you're back we could try your bulb in my switch and vice versa if you like.

[Nathanb]

Hi Jonathon thanks for the offer, I would have taken you up on it but I've managed to get the old bulb working, but good to know that you're local.

So it looks like the LED replacement is not working. It lights up [very very dim] when using the multimeter, but strangely enough the multimeter doesn't make the audible resistance sound. I then used a wire connection to both the copper strip and spade connection on the LED and no joy. Will have to send it back.

As for the original bulb, I tried the multimeter on it, no joy. Then noticed that the bulb was a little loose in it's housing. Pushed it back in then plugged it back into the Fog Light switch and hey presto it's now working again!!

[MidLifeCrisis]

So it looks like the LED replacement is not working. It lights up [very very dim] when using the multimeter, but strangely enough the multimeter doesn't make the audible resistance sound.

Not quite sure what you mean by this - are you saying that you tried to light the LED using just the multimeter? Because I'm pretty sure that wouldn't work?!?!?