I have a similar issue with my 1992 6Cyl 4WD pickup where the reverse lights have stopped working. I haven't solved it yet; However, I did find a place to start.
http://www.yotatech.com/f116/do-your-backup-lights-don't-work-118636/#post50557464
Do your backup lights don't work?If so check this out.
My backup lights have not worked since god nows when..
so today I finally drag myself under the truck and look around for the reverse switch thing (2 prong switch that sticks out from the tranny)
on mine it was on the passenger side, very easily to see.
At first I could see that the plug was only halfway on, so I think "oh yeah, easy fix" so I plug it all the way in, put my key to the "on" possison and put her in reverse, go to the back of the truck.. nothing.
So okay, I crawl back under the truck and kinda think for a second.
I then realize that the switch can go on upside down and you cant tell the difference.
So I flip the wire around and plug it back in and what do I see when I go to the back end of the truck?
My reverse lights work!!
So if anyone has has tranny work and since then the reverse lights don't work, try this, its pretty easy to mess up the switch since it plugs in perfectly right side up or upside down, so the shop might have plugged it in upside down
Bad bulbs can be the cause of your reverse lights not working on your 1999 Toyota Tacoma. A problem with the reverse switch or bad wires can also be the cause of your reverse lights not working.
how do you bypass electric window switch on 88 toyota pickup
To change the reverse switch on a 1999 Toyota Solara, first, ensure the car is turned off and the keys are removed. Locate the reverse switch, which is typically found on the transmission; disconnect the electrical connector and unscrew the old switch. Install the new switch by screwing it in place and reconnecting the electrical connector. Finally, test the backup lights by starting the car and shifting into reverse.
There is a switch on the shifter or trans that turns on the lights when the vehicle is placed in reverse, it is out of adjustment or faulty. And don't forget the bulbs or fuses as a cause.
There is a switch called the reverse backup light switch attached to the shifter. When you move the shifter into reverse, the switch is closed and current goes back to the reverse lights. The switch is located on both auto and manual trans. After making sure your bulbs are good, that is where I would look. And make sure your fuses are not blown as well in your fuse block. There usually is not just a circuit dedicated to reverse lights only but there is always something a manufacturer will do some years just to be different.
Try bypassing the reverse light switch that plugs into the transmission. If your reverse lights come on, voila! Problem solved. Buy a new switch.
Where is the fuel pump relay switch located on a 1994 Toyota pickup
Apperently there are no fuses for the reverse light. First check the wiring that goes down the trunk. The wire tend to split due to the trunk going up and down.
There is a backup switch in the gearbox. When you shift into reverse, the gear box switch contacts the switch and lights the white reverse lights. If you find that the reverse lights don't work it could be that the switch is not being triggered by the mechanism inside the gearbox. This is providing that everything else is working; wiring,bulbs,etc.
The 1986 Toyota pickup flasher relay switch is located beneath the dashboard on the drivers side of the passenger compartment. The flasher relay switch will be labeled as such.
Check fuse Check bulbs Check switch-usually located in side of transmission Check wiring
You may have burnt out bulbs, blown fuse or malfunctioning brake switch. Same on any car.