E36 Headlights repost.

[Kurt Sampara]

97 M3 - New (reman)alternator which works (don't buy one, they are loud). The car is throwing a "low beam failure" code. The fuses and relays are fine. With the light switch in the on position the High beams still work but no lows (both). Where should I try next. The switch seems logical, but the high beams still work? Maybe the stalk which turns on the high/low beams? I am stuck.

[Manolito]

Trying to look at the wiring diagram but I left both pairs of reading glasses at the office.

USA and Canada cars have different fog light and high beam wiring, but that should not matter for this.

1) My suggestion about the check control module was bogus. This one is wired in parallel rather than in series, so a module failure will not kill your lights.

2) Starting at your low beam light socket, the brown wire should be ground (zero resistance between socket and your chassis).

3) The yellow/green wire should be hot back to Fuse 11 (left light) or fuse 12 (right light).

4) From the fuses, the white/blue wire should be hot back to terminal 87 on the low beam relay.

5) The red wire to terminal 6 on the low beam relay should always be hot. It goes straight to the power bus for the fuse box, I think.

6) The brown wire to terminal 85 on the low beam relay is ground.

7) The yellow wire to Terminal 8 on the low beam relay comes from the switch on the dash, but also attaches to the switch on the column. Should switch on and off with the switch on the dash. That wire must be hot at the dash switch or you would not have high beams.

The switch on the column is just used to toggle on the high beams and flash the high beams. The low beams should work whether that switch works or not.

8) The green/yellow wire to the switch on the column is hot when key is on, from Fuse 23. But that is just used to flash the high beams.

Good luck!

[Kurt Sampara]

I am going to go in my back yard and dig a hole and sit in it! Then go and buy a Lottery ticket. Both my low beam H1 bulbs were bad? What are the chances of that? I wonder if the new alternator had something to do with it. Anyway, thank you all so much. K.

[Jeron]

Didnt I mention the voltage regulator in the other thread? http://forums.pelicanparts.com/showthread.php?t=416611

That could blow both low beams.