HID Bulb Flickering (Even when the car is off)

[CrazyCal]

Having an issue with my driver's side headlight. The HID bulb (low-beam) on that side flickers...even when the car and lights are turned off.

The ignition was off and key removed and the headlight switch was turned off as well and it still does this...




It burned out my bulb on that side. I swapped one of my old bulbs in. Still flickers.

I unhooked the bulb on that side and ordered a used, good condition ballast. Swapped the new ballast in tonight and found no change. The bulb continues to flicker in the same fashion.

I wanted to see if the issue was isolated to the headlight unit itself or elsewhere in the car, so I removed my passenger headlight, swapped both headlights entirely by flipping them upside down (to match the plug) and plugged them both in. It continues to be the driver's side that has the issue. Likewise, the swapped driver's side headlight unit (to the passenger side) had no issue. So that means the issue is elsewhere in the car/wiring, but isolated to only the driver's side.

What could be causing this?
Headlight Switch?
Wiring?
Central Electric Control Module, aka "Onboard Supply Control Unit"?

^
Discovered that here when finding out that headlight relays can be responsible for flickering, then.... found out HERE that the B6 doesn't have any headlight relays. They have a Central Electric Control Module instead.

[ADCS]

Definitely wiring.
I am not familiar with the headlight schematic but it sounds like a switched 12v is shorting to a constant 12V.

[freeloader700]

Disco headlights!

I would second and say it could be the wiring

[PreciseD]

You might want to check your headlight relay. I have seen this issue where the relay is shorting out and just needs to be replaced.

[SaabtoAudi]

May want to check out the harness. I had the Dipped Headlight, and the bulb stopped working. Spent 120$ on ebay for CBI bulbs. As i found out, my wiring was shorted on both bulbs.

Fixed wiring, factory bulbs both worked. Couldn't return the old ones, so I installed them, and then will keep the factories for backups if the ebay ones fail.

[freeloader700]

^^
Thats bad....


The ballast to bulb wire is another thing that seems to have a weak spot. Maybe swap those around, Cal. See if that changes anything. I might have an extra I could give you. Also if it looks like the internal harness on the head light is faulty and you want to swap a different headlight in, PM me. I have a stock set

[JEENYUS]

what is crazy to me is that the bulb does this even when the car is completely turned off?! i guess which craft really does happen...

[CyberPMG]

I would check the wiring around the switch. If you have an aftermarket stereo installed, check the wiring around that to make sure everything is grounded. Both the radio and the headlight switch have constant power, so they could be tied together (not 100% certain).

[CrazyCal]

You might want to check your headlight relay. I have seen this issue where the relay is shorting out and just needs to be replaced.

The B6 does not have headlight relays.
As I said in my post, it has a Central Electrical Control Module instead. It's right in the row of relays under the driver's side of the dash. That's kinda what I'm thinking it is.

^^
Thats bad....


The ballast to bulb wire is another thing that seems to have a weak spot. Maybe swap those around, Cal. See if that changes anything. I might have an extra I could give you. Also if it looks like the internal harness on the head light is faulty and you want to swap a different headlight in, PM me. I have a stock set

As I said in my post I swapped both entire headlight units to their opposite sides to rule out anything inside the headlight unit.

[PreciseD]

Yeah you are right... Jumped the gun on that one. I did have a bad relay on my G35 that caused flickering so that's why I suggested it. I had no idea the Audi was controlled with a module. Maybe is someone has a B6 near you then you can swap them to see if that's the problem.

[freeloader700]

Missed that spot...Didn't you hack up/modify the harness a bit in the past? (can't remember where I seen it) Could it be some sort of a short there?

[SJorge3442]

Hmm. This is strange. Once you find the problem, you should get in touch with that guy who wanted his headlights to flash. Maybe he could use this as his "car show mod".....

[evo_ski]

Hmm. This is strange. Once you find the problem, you should get in touch with that guy who wanted his headlights to flash. Maybe he could use this as his "car show mod".....

LOL! Nicely done.

I wish I had better advice aside from tracing the wires all the way back, but that doesn't really sound feasible without a massive amount of parts being pulled off. I guess the CCM is the only other possibility.

[customa4]

Here's a post from Diagnosticator regarding the CECM when someone was experiencing a similar issue, just with brake lights instead. That's weird that it's happening when everything is completely off, your car is possessed.

If the reverse light on one side is flashing, the only cause for this is a defective Central Electric Control Module. Since the module is faulty, that is also most likely why the brake lights are not working right. The CECM powers and controls all of the exterior lights. there are no fuses.

Thread about brake light.

[daverdfw]

maybe pull the fuse for the CECM? and isolate if the power is coming from there?

[freeloader700]

That's a very good idea


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[CrazyCal]

Missed that spot...Didn't you hack up/modify the harness a bit in the past? (can't remember where I seen it) Could it be some sort of a short there?

No. I never hack into stock wiring if I can help it. I piggybacked resistors into the headlight plug for my LED turn signals. I checked the plug and all of that looks good.

Modified the headlight switch with "little more than 5 minute" mod for fogs. But that doesn't really matter anyway since the headlight switch only has one "on" pin for headlights. Being that the issue is limited to one side, it wouldnt make sense that would cause a problem.

LOL! Nicely done.

This

maybe pull the fuse for the CECM? and isolate if the power is coming from there?

Where do the headlights ground? If they ground through the CECM, then pulling the fuse wouldn't help because the power (from the alternate source) would have no ground to complete the circuit.

[CrazyCal]

what is crazy to me is that the bulb does this even when the car is completely turned off?! i guess which craft really does happen...

Just caught this. Har har. I chuckled.

[CrazyCal]

My hunch was correct. The Central Electronic Control Module was the problem.

I ordered a used 8E0907279F module, but the seller accidentally sent me a
8E0907279E (the old version found in 2002). I'm going to send it back and get the F module, but before I packed it up, I tried the E module and it solved the headlight issue.

Now I just need to get an F module and pop it in!

[diagnosticator]

Yeah, when bizarre exterior lighting malfunctions occur, it is almost always the CECM.

[CrazyCal]

Sooooooo this issue really sucks.

Bought and installed a new CECM. It all appeared to work... initially. I tested it in my driveway and it all appeared to be working fine. I drove in to work and, once I got to work, I noticed it the headlight flickering again. Son of a bitch.

Also, I noticed the compass mirror flickering. The digital readout and the little indicator light on the bottom of it. They flickered a weird, random pattern. It could be something new, but it's very likely I didn't notice it the last time this happened. The two issues are related though, because as soon as I unplugged the cable from the HID Bulb in the housing, it went back to normal.

So, what now? Wiring, I suppose....
I have no idea what I should be looking for there.

[CrazyCal]

The issue has been fixed. I feel stupid, but whatever, it's fixed.

It wasn't the Ballast or the Central Electronic Control Module. It was the "bit longer than 5min" mod I did to my headlight switch. The electrical tape used to cover up the fog prong (pin 16) ripped and slid down exposing the prong and allowing the connection, defeating it's purpose. The other prong involved (pin 17) is the positive for the instrument panel. So that explains all of the electrical weirdness.

I still find it odd that the flickering was isolated to only the driver's headlight, but it also effected other things like the lights and digital readout on the compass rearview mirror so who knows...






On another note...if you do ever need to install a new CECM, you should have a vagcom available to run the VIN learning process. A used module will, obviously, have a different VIN and you will not be able to recode it if it doesn't match your VIN.

To do this with vagcom:
- Access 09-Central Elect.
- Go to Adaptation
- Access "Component Protection" from the drop-down menu.
- Enter 46922 under "New Value"
- Hit enter on your keyboard then press save and give it a few seconds to process. Done!

[AUDIocee]

Just saw this post, isn't the fog light mod to wire together pin 1 and 2, then tape up 2? [Xr] [ Xz] pins.