I have a 1987 4x4, 22r, 5spd.
When I turn on my left turn signal, my reverse lights flash along with the front and rear turning lights. When I put it into reverse, my left turn signal bulbs light up.
I have checked the wiring from the transmission, all the way through the switch, to the rear tailights. I have resoldered the grounds on the left rear sockets (one of the points was loose). I have removed the trailer harness and checked to make sure the wires were not damaged.
I have been pulled over twice because, as the cop said "My rear lights were acting crazy." I don't know when the same cop is going to see me turn left again, but I would like to straighten this out. Any pointers will be appreciated!

 

Just fixed a problem like this today on my 79. Pull the rear harness and strip the tape and loom off, and check the White/Black wire (ground) factory splices....

Mine were corroded and pulled out of each other, causing stupid things like the brake lights and turn signals to work in unison, and hazards to only flash the fronts.

 

remove the reverse light bulbs

 

Solves alot, then run some fogs and a switch for rev. lights

 

there ya go; no more blinking reverse lights, plus you NEW reverse lights will be a lot brighter just don't leave them on

 

Get real bright lights...then they'll double as anti-tailgater lights

 

Start simple. Try cleaning the battery terminals first.