Mrspencer

My 85s3 reverse lights are non op, have checked the fuses, relays, all ok bulbs good, also changed the reverse light switch, still nothing, AÀAARRRRHHHH. SO FRUSTRATING by the way it's a 5spd.

Jeff Bowlsby

Clean the rear ground?

GlenL

Gotta get the wiring diagram out and check it out at each step along the way.

It could be the 4-pin connector at the front-right of the spare tire well. You can check the action of the switch there, too. Unplug, clean and re-plug.

JBGold07

Try trace the wires from the gearbox switch back to the connector in the spare wheel well. Two wires, running above the gearbox, look for a break in a wire and poor connection at the switch

WyattsRide

I had problems with my reverse switch also. Still do somewhat. I also replaced the switch. I seem to remember there being a little actuator rod in the switch. If it went in too far the reverse lights would always stay on. But, if I backed the switch out some (not screwing it in all the way) the lights would not work. I added a thin washer and found the sweet spot. Not sure if this was the "correct" fix but it seemed to work. I still have intermittent working reverse lights but if I hold the gear shift **** tight in reverse, the lights stay on when reversing.

Mrmerlin

before you get to far inspect the 2 wire plug on the bottom of the steering wheel lock cylinder if its loose or not connected this could cause the reverse lamps to stay off.

I chased this with a 1986 machine and found it.

on mine the wires were just loose enough to not make contact,
putting them into the switch then all the lamps worked

gazfish

+mrmerlin if it's an auto and the shift indicator on the dash and the reverse lights only work when you have your lights on.