QuestionQUESTION: 1999 Audi A4 V6 30V quattro / 5 speed.
My headlights won't turn on.
I can flash the highbeams but the regular circuitry doesn't get the power to it when I have the key on. I jumped power from a constant source to the feed side of the low beam fuses and the lights go on plus the hi/low switch works (but I don't want to go to hi because I'll be drawing hi and low from the single fuse). I looked in the shop manual and it appears that the "A51" connector isn't getting power. Of course I don't know exactly where "A51" is located. Is there a load reduction relay specific to the headlight circuit? Everything else (including parking lights, turn sigs, cruise, hazards) seems to work. I'm quite handy with electrics (owned a car stereo business for 15 years, build / wire race cars and all sorts of electronic stuff.)
Thoughts?
JimB
ANSWER: hello
I will look in the manual monday or letter. I away for next 3 days, but we had many ignition problems on A4. Most of the time people complain about lights, turn signals or wipers do not work. When you pull out ignition switch you can see crack on where it meets with mechanical part.
If you can check the switch first and let me know, so I will look more on wire diag.
good luck pltech
---------- FOLLOW-UP ----------
QUESTION: I don't think this is related to the ignition switch as all of the other functions in the car work fine / all of the time.
In further researching this it appears that the main power for the headlight circuit is through the headlight switch (on the column). I suspect that the switch is bad. Take a look at:
http://www.audiworld.com/tech/elec114.shtml
I have 100 watt bulbs in the high and low beam circuits so I may be drawing far more current through that circuit (headlight switch) then it can handle (40 amps with 4 x 100 watts versus half that for stock) and as such I'll likely have to replace the switch and then put in separate relays to handle the load.
On Saturday I was running "fast sweep" (tracker) at a performance rally (www.stpr.org) and would run down the stage road for an extended period of time with my high beams on. It would be rare in normal driving for me to have my highs on for more then a minute so that extra load proabaly melted the contacts / housing.
Take a look at the schematic and let me know if the current for the lights all passes throught he switch. I sense a trip to the dealer :).
Thanks!
JimB
Answerhello
Once you wrote about switch I remember we just had 98 A4 with bad switch , and power was going through the switch.
And just like your A4 everything else was OK.
I was looking at diag. and we only have Canadian one witch has daytime running lights. It show 4 wires , 2 are going through the switch and others through some front light module (looks like double relay in 4and5 position ) under the steering wheel. I Checked my mom's 01 A4 and did not have this relay, so most like it it's only on Canadian models.
You can check for power at the switch . Power comes in on yellow/black 2.5 gauge wire, goes through the switch and comes out yellow 2.5 wire. If you jump these two lights have to come on.
good luck pltech
