Tom Faust

I have lost high beams in my '90 100. I assume it is the switch. Anything else I should check. I forget if high beam indicator comes on or not. Does it matter?

tonyj

Switch is a probably cause except that when the switch breaks you are usually left with high beams only.
Check fuse but I think that the fuse is for both high and low beams. There is also a headlight relay.
A bad switch usually feels like it has broken. If you need the switch you need to pull the air bag and steering wheel. Careful on the air bag and follow manual or let a mechanic do it.
The switch is part of an assembly that will cost 120 to 250 depending on if it is split into right / left halves or one unit for all the controlsand where you buy it.
I like Shokane 800-ALL-AUDI

Tony
'91 100Q 5spd

Will Ng

If dash high beam indicator comes on but the high beams are out, then I believe the combo switch is ok.
There are 4 fuses, one 10amp fuse for each beam, in the under-hood fusebox.
Another thing to check is the load reduction relay in there. It cuts off high current items during starting. But if it's bad, you would not have a bunch of accessories, not just high beams.
It's not hard to check the combo switch with a multimeter. Remove the plastic cover over the stalks...it's just 2 phillips screws. The steering wheel can stay on. Once off, all the wiring is exposed, and you can probe to see if it passes voltage.