on my 1986 244GL.

The reverse lights are not on the bulb failure system, so there is only one wire going back to the tail lights. It's black, like Tommy said.

You will need to pull the spare and pull the left tail light cover. Then set up the car so the reverse lights should be on - key on, trans in reverse, etc.

Grasp and wiggle the white connector that attaches the harness wires to the circuit board, and watch the lights. If they change, here's the problem:

On the circuit board, where the wire terminals grip the board, the foil for reverse lights is double-wide, gripped by two grippers. One black wire from the front, and another right beside it that takes voltage over to the right side light.

The foil gets corroded, oxidized, burnt and otherwise non-op. (Can happen to any of the lights.) The foil under the gripper going to the right side reverse light is probably OK, it's the one where the voltage from the front connects that goes bad.

Take the white connector off the circuit board, and open it up - one long side is a hinge. Use needle-nose pliers to pull and replace the black wires, swapping the positions. This will make the wire from the front grip a good spot on the foil, and light up the left reverse light.

The right side reverse light may or may not light up - depends on how bad the foil is messed up. BUT - one reverse light is way better than none.

I did this "fix" because I back into a tree-lined driveway and I got tired of having only the emergency flasher and LH fog light illuminating my path.

BTW The fog light is LH only as I did the same "fix" on it.

Good Luck,

Bob

:>)