switch is on the transmission
Pretty sure it's on the driver's side transmission. It's integrated with the neutral safety switch...
Did you just recently have a remote starter put in ? I had the same problem with my car and I took it back to the shop and they reset the ABS switch and I had no further problems.
Inside bumper back of it
I was told by my parts guy that the back up light switch is the same as the reverse light switch.
the back up light switch is located in the gear shifter console
I had a 97 F150 with the same problem. Per internet advice I removed master light switch from steering column and cleaned the green corrosion. This gave me my highbeams back. Later when I had $100 for a new switch, I replaced it and the headlights have been working fine ever since.
You can try to reset your brake light switch by unplugging the brake light switch and plugging it back in. If that does not solve your problem you will need to replace the brake light switch.
the back?
On a 1989 C1500, the back up light switch is located on the driver's side of the transmission. It is just behind the area that is bolted to the motor.
bad fuse , bad electrical connection to or bad switch ( back up light switch on manual transmission / neutral safety switch on automatic transmission also acts as backup light switch )
you can find the switch on the back of the brake pedal.
When the shifter goes to the reverse position a switch is depressed to turn on the back up lights. The switch is most likely on the top of the transmission.