I recently purchased a 2002 A4 quattro and just converted the stock headlamps over to HID. I installed the kit and it worked fine but when I turned the car on I got all sorts of warning lights: the traction control light was on, the BRAKE light was flashing repeatedly, and it was beeping at me. I got online and found that there was probably too much initial draw from the ballasts and it was firing a "red flag" to the computer and tripping the warning lights.

This is how I thought I would fix things:
I re wired the HID kit to two separate relays (one for each ballast) and wired it all directly to the battery, using the factory headlight socket as the trigger for the relay. The lights work great and all of my warning lights went away but now the car thinks that my front headlights are out and flashes that warning instead. Is there a way I can trick the computer to get rid of these warning messages? It seems a little odd to me that Im getting these errors even though power is flowing through the factory headlight harness.

any help would be great, thanks,

Sporttracguy

it may also be where u had mounted the ballast causing interfernce

headlight warning was on all the time when he switched to hids..he just ignored it lol.
ddm tuning sells a warning code eliminator, not sure if it works for our cars though?

I just posted a similar question. My left and right dipped bulb errors are going off. Thought they would b/c the one low beam housing is not hard wired. I used a relay b/c I read that if you didn't you would have intermittent problems. Lights work great but I'm trying to find out how to bypass the errors. There just annoying...nothing too big.

P.S. I tried clearing the errors with a Vag Com tool but it didn't work

Oops! You should have connected a computer warning canceller.
That is intended to solve the problem encountered during the installation of HID kits on certain car models, like Audi. BMW and MBenz.

The computer error may show up as a "CANBUS" error.
The power supply is connected with the ballast via the warning cancellers.
Whether it actually does the trick or not is another issue.

I've been told by an Audi bodyshop fellow that, in the very worst case scenario, fitting HIDs to an Audi can destroy the car's electrical circuit.
That's a very expensive risk to take and, personally, I don't think having HIDs is worth that expensive a risk.

alot of fellas here and on audizine and audiworld have been running aftermarket hids for over a year now with no problems. Ur guy is wrong.

"Ur guy" of course may be right if there are no controllers put between the ballast and bulbs, and he is wrong if there are!:)

I posted this some years ago. Maybe it will help explain the light warning with HID installations.

The BMW warning circuit runs a tiny DC current thru the bulbs in order to determine whether the bulb has blown or not. This is done when the key is turned on without the lights on.

This works fine for incadescent halogen bulbs which contains a filament and a closed circuit will indicate that the filament is intact. If the filament is blown, then the curcuit will be open and hence the warning indication.

HIDs do not have filaments and under normal circumstances, the circuit will always be open. The current used to run the HID bulbs is also AC. Original BMW HIDs fitted to cars as original equipment caters for this in both the curcuitry and the warning programming.

Fitment of aftermarket HID will cause this light warning to come on. Most after-market HID kits specifically made for BMWs comes with a bypass circuit with a resistor (not a capacitor) either as an add-on or built into the balast to "fool" the diagnostics. The bypass circuit will allow a small current to pass thru to produce the closed circuit like as if there is an intact filament and prevent the warning but will not be live when the lights are switched on or when the car engine is off to prevent battery drain.

You might put a resistor, 7 ohms 20 watts, in parallel.
This will draw 55 watts instead of 35 watts.

what kinda kit are u running

My HIDs with controllers are working great. No bulb warnings.

The headlights are powered by the Central Electric Control Module. Either the halogen lamps or the OEM xenon ballast are matched load to the CECM without resulting in the "dipped" headlight warning. Therefore, the load resistance of the aftermarket non OEM ballast is too low and trips the dipped headlight warning. The best remedy is to use OEM xenon headlights and ballasts that are plug and play compatible with the rest of the electrical system. Alternatively, try increasing the load resistance by placing a 220 ohm 1 Watt PDR rated resister in Parallel with the ballast power input circuit.

BTW, converting halogen headlights to xenon, is dangerous to other drivers due to the excess glare that results from the conversion, and is illegal everywhere.

@diagnosticator1

Re "The best remedy is to use OEM xenon headlights and ballasts that are plug and play compatible with the rest of the electrical system"...

Technically, yes.
Cost wise, no.

"converting halogen headlights to xenon...is illegal everywhere"...

From personal experience, that seems to depend, since my Allroad was MOTed and it passed with an aftermarket (non-OEM) Xenon conversion.
Seems that when the vehicle has self-levelling air suspension that ensures no load-induced excess glare, and lamp washers, it's OK.

i passed inspection and have aftermarket hid setup in a halogeon capsule. i dont think lamp washers has anything to do with making the lights function properly. AS long as u have projectors for ur lowbeams u should be okay. Just make sure to aim properly.
http://www.ehow.com/how_4962528_aim-headlights.html

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sporttracguy, if you read through the thread regarding HID and how to avoid warning lights, you may notice a keyword - CONTROLLER.

Put a controller between the ballast and the bulb and that will handle warnings.

It's that simple!

what kinda kit are u running
Sorry, I can't recall. All I remember is that the accessory dealer had to special-order the long beams, as they are rare'ish. I have HID short + long beams installed + a controller for each.

Thanks for all the info guys. Very informative thread

i passed inspection and have aftermarket hid setup in a halogeon capsule. i dont think lamp washers has anything to do with making the lights function properly. AS long as u have projectors for ur lowbeams u should be okay. Just make sure to aim properly.
http://www.ehow.com/how_4962528_aim-headlights.html

Hey thank alot for that link.

best way to get a deecent ambient recording of a kit is Kick Snare and 2 Overheads.

As long as your have good balance around the kit you will be fine.

Yes of course, you can over load the BCM. If you want to go all out you could use the power that would normally go to the lights and put a relay in. If the lights youre currently using are the same watts and youre not adding any extra lights then you should be good to go.

Have you checked a common auto parts store for the bulb?