Electrical Issue, Brake Lights/Taillights, PLEASE help! Fault 00988

[excelon53]

PLEASE, someone help me. I'm pulling my hair out.
A little over a year ago on a summer drive to Vegas, in the extreme heat 120 degrees or more, both of my outside brake lamps went out (4 bulbs) went out with warnings in the dash all of a sudden. I checked the bulbs, they were fine, I ended up replacing the entire taillight assymbly thinking it was the chip or wiring inside the housing, none of that worked. Only my inner taillights (on trunk) light up when braking and the outer LED lights up more when I hit the brakes.

Is there a control unit somewhere that may have shorted out? Are there any other fuses that I don't know about?

I just replaced the brake switch at the brake pedal and that did nothing.

Thank you for your help!

This is what it looks like when braking, the LED should not be lighting up at all.

Here's the results:

 

[Ash187]

I would guess at a wiring fault... Get a multimeter and get testing
maybe the heat melted some wires together?

 

[excelon53]

I would guess at a wiring fault... Get a multimeter and get testing
maybe the heat melted some wires together?

Thanks for the reply. Where do you think they could have melted? Everything looks fine behind the light housings. Do you know of any electrical control boxes or relays for the brake lights?
I feel like what you're saying is right, but I just can't imagine an entire wire melting together. Seems more like a relay getting to hot and shorting out..

 

[excelon53]

Help bump!

 

[Artimus]

I'm not sure it's the wiring at all.

I'm almost certain I've seen options to alter the brake light configuration in VCDS, but since I'm fairly new to VCDS ownership, I couldn't tell you where to look! You could try posting in the VCDS section asking for info on programmability options.

 

[excelon53]

Thank you, yes you are correct and everything is configured correctly in VCDS. They were working perfectly fine before the heat. It has to be either a relay, a faulty ground connection, a short (melted wires), or a faulty ECU. I just don't know how to find the relay and or grounds associated with brake lamps.
Anyone??

I'm not sure it's the wiring at all.

I'm almost certain I've seen options to alter the brake light configuration in VCDS, but since I'm fairly new to VCDS ownership, I couldn't tell you where to look! You could try posting in the VCDS section asking for info on programmability options.

 

[Boon]

I'm sure there is a control module behind the boot (trunk!) side panels, I found one when looking for a leak!

The one I found was right in the rear corner at the bottom, 1 set of wires went in from the car loom and to other went to the lights, might be worth having a look at these?

 

[excelon53]

I'm sure there is a control module behind the boot (trunk!) side panels, I found one when looking for a leak!

The one I found was right in the rear corner at the bottom, 1 set of wires went in from the car loom and to other went to the lights, might be worth having a look at these?

I'll see if I can tear apart my trunk today. So frustrated with this!
Thanks again for every ones input!

 

[excelon53]

I'm sure there is a control module behind the boot (trunk!) side panels, I found one when looking for a leak!

The one I found was right in the rear corner at the bottom, 1 set of wires went in from the car loom and to other went to the lights, might be worth having a look at these?

So I took out that control module and turned on the car and the same warnings came on (Right and left brake bulbs)

I'm at an absolute loss with this. There has to be some logical explanation. Does anyone have a wiring schematic for A3s? Does anybody know if any of the relays under the dash have to do with brake lights?

 

[Artimus]

if you get the exact same errors with the module removed, does that not point to a dead module?

 

[excelon53]

if you get the exact same errors with the module removed, does that not point to a dead module?

You know, I'm not sure. I just assumed if that was the module for tail lights, then they wouldn't work at all if it was removed. And they continued to work the same with no new warnings. Although I was certain that was for the taillights since it says "hella" on it, which is usually associated with lighting. I suppose the only way to know would be to replace that unit as well. I just don't want to keep replacing things that are working fine, like my brake light switch.

 

[excelon53]

Just ordered an entire new relay Electrical Control Module. We'll see if swapping that out helps. Does anyone know if I have to code anything or can I just straight swap if it's the same part?

Power module. Audi # 8P0907279P

 

[NHN]

TBH I cant imagine that heat will make the outer covering melt, they're heated up to far more than that in production imho, certainly they would prepare for heat of this nature in some enviroments.

I would disconnect each circuit, check all your coding, various things 1st & yes the CE Module 279 version controls those systems, so worth a go with another to see if this resolves.

 

[excelon53]

TBH I cant imagine that heat will make the outer covering melt, they're heated up to far more than that in production imho, certainly they would prepare for heat of this nature in some enviroments.

I would disconnect each circuit, check all your coding, various things 1st & yes the CE Module 279 version controls those systems, so worth a go with another to see if this resolves.

Thank you for the reply. Yes I thought the same thing, but they indeed did indent from the heat. I left the car in direct sunlight with the back end facing the hottest part of the day sun. It reached temperatures in excess of 125 degrees, so I can imagine direct sunlight could get the lens up to over 200. I'm assuming the pressure on the inside created a vacuum effect as they cooled in the evening and caused indents. Either way, the electrical issue didn't come until I was on my drive home to Los Angeles. It was a traffic jam and I had my foot on the brake for several hours. It was still over 100 degrees at night, that in combination with a constant on circuit, something had to of melted or shorted.
Last question, if I'm replaced the 279 unit with the same unit, do I need to code anything with VCDS or will it automatically work? I was under the impression that all the coding is through the ECU and everything else just directs where to send that information?

Thank you again, I really appreciate the input.

 

[excelon53]

Here you can see the indent. Took this before I replaced the housings. The other side got an almost identical indent..

 

[NHN]

Strange as looks like its a spot melting point, I would challenge audi on that tbh mate.

 

[excelon53]

Feast your eyes on this! I couldn't believe this when I pulled it out and popped it open. This was definitely the culprit!

Now if I can only figure out how to code my new 279. Do you have the coding I need for that? It must be off a different model A3 because my brights aren't working, my side markers are always on, my turn signals are coming on with my brakes etc.

 

[excelon53]

So I researched some other threads on this, and turns out I bought a different version of the 09 unit. I went from 8P0907279F to 8P0907279P. Will the P version work with my originally F car? I have a 2006 Audi A3 Sport with Xenon auto-leveling headlights.
Any help would be greatly appreciated.

 

[NHN]

The F supersedes to a K & the K supersedes to a P, so you're perfectly ok with that, just look at your current coding tickbox names & tick the same boxes with same names within the P module, also the same timing values.

I still think you need to challenge audi about the heat deformed areas on rear lamps.

 

[excelon53]

The F supersedes to a K & the K supersedes to a P, so you're perfectly ok with that, just look at your current coding tickbox names & tick the same boxes with same names within the P module, also the same timing values.

I still think you need to challenge audi about the heat deformed areas on rear lamps.

Sorry, I'm new to all of this. Does this mean I need to put my K back in to find out the coding on it first and write it down and then reinstall the P unit?
Thank you for your help!
As for the taillights, I think you're right but I already sold them to someone "as is."

 

[NHN]

Given its a supersede, you could just copy & paste although I tend to shy away from advising this as a rule of thumb , but to cover your butt as such, just do screen dumps of each byte page showing tick boxes & manually go into P & tick the boxes & set the numbers for lights, to avoid any mis-coding as such.

 

[excelon53]

Sorry, I'm new to all of this. Does this mean I need to put my K back in to find out the coding on it first and write it down and then reinstall the P unit?
Thank you for your help!
As for the taillights, I think you're right but I already sold them to someone "as is."

Got it! Last question. In order to get that screen grab do I need to physically put my old 09 unit back in and then hook up to VAG-COM? I have the new P revision in now. So basically do I need to swap them back to stock to get the numbers? Or will the same numbers already be there with the 09 P installed?
Thank you!!

 

[NHN]

Yes swap back, do screen dumps of each page & then tick each box manually on the P corresponding to the K.

 

[excelon53]

Sounds good, thank you so much!!

Got it! Last question. In order to get that screen grab do I need to physically put my old 09 unit back in and then hook up to VAG-COM? I have the new P revision in now. So basically do I need to swap them back to stock to get the numbers? Or will the same numbers already be there with the 09 P installed?
Thank you!!