Golf IV Electrics Knocked Out by LED Brake Light Bulb

[nkoulban]

Hi Fellow Watercoolers,

I fitted LED brake light replacement bulb to my MK4 Gold Sport and it has caused the following to stop working:
1. Remote Lock/Unlock
2. Electric windows
3. Sunroof
4. Lights on Chime

I checked the fuses, they seem intact... so I started to get worried.

I will disconnect the battery to see if that sorts it out... failing that I may have had an ECU fail.

If anyone has had a similar issue, I'd appreciate any ideas or feedback.

Thank you

[Manaz]

Did putting the stock bulbs in place fix the problem?

It's extremely unlikely that LED bulbs killed your ECU, though confusing it is a definite possibility. Make sure that the LED bulbs you've used have the correct resistors across them so that the bulb "looks" like a standard bulb to the car. Otherwise you'll face exactly these sorts of issues.

[JustCruisn]

^^ What he said.
Undo your last step to begin trouble shooting.
Check the fuses with a multimeter or test light. Don't just rely on a visual.

[nkoulban]

I put back the stock bulbs and the said electrics are still out.

Did putting the stock bulbs in place fix the problem?

It's extremely unlikely that LED bulbs killed your ECU, though confusing it is a definite possibility. Make sure that the LED bulbs you've used have the correct resistors across them so that the bulb "looks" like a standard bulb to the car. Otherwise you'll face exactly these sorts of issues.

[nkoulban]

Thanks for the tip, I'll check them non-visually as well.

^^ What he said.
Undo your last step to begin trouble shooting.
Check the fuses with a multimeter or test light. Don't just rely on a visual.

[Stan]

check the wiring in the holder too, make sure nothing got shorted out when you replaced the bulb

[nkoulban]

Looks like the comfort module Karked it. I will do further investigation to confirm. I hope a Comfort module is not too expensive to replace.

check the wiring in the holder too, make sure nothing got shorted out when you replaced the bulb

[Givemecoffee]

Hey, could you take some photo's of access to your comfort control module if possible? I'm really short on spare time to go digging around for mine and I think it needs replacing or at least checking (I've got all sorts of electrical issues). Thanks!!!

[Stan]

CCM from about 450 and up on ebay. Make sure you get the right part number, and some have two plugs and some have one so be careful.

givemecoffee- see if you can scan your car, might help

[nkoulban]

I'm dropping off the car to a mechanic to fix... I diagnosed it with the help of my brother in law, I'm a hopeless mechanic.

Hey, could you take some photo's of access to your comfort control module if possible? I'm really short on spare time to go digging around for mine and I think it needs replacing or at least checking (I've got all sorts of electrical issues). Thanks!!!

[nkoulban]

Yay, all fixed. Needed an new comfort module, rear wiring harness and a welding job as the rear gas strut ripped itself out of the C Pillar! Some advice, don't be tempted to use LED globes.

[Manaz]

Yay, all fixed. Needed an new comfort module, rear wiring harness and a welding job as the rear gas strut ripped itself out of the C Pillar! Some advice, don't be tempted to use LED globes.

There's plenty of people using LED globes - you just can't use cheap ones without knowing what you're doing...

[nkoulban]

What are the right ones to use on a MKIV Sport or what specs I should look out for?

There's plenty of people using LED globes - you just can't use cheap ones without knowing what you're doing...