I have a 1989 GMC Sierra C1500. Recently, all my rear lights died, tail lights, brake lights. Also the inside dash panel lights died. These did all work until recently. I have replaced all the fuses, and all the bulbs, and nothing. Anyone have any ideas of what could be causing this?

Thanks.

Switch has a short? Brake switch, reverse switch panel dimmer switch ( the last is my first guess)

I have a 1989 GMC Sierra C1500. Recently, all my rear lights died, tail lights, brake lights. Also the inside dash panel lights died. These did all work until recently. I have replaced all the fuses, and all the bulbs, and nothing. Anyone have any ideas of what could be causing this?

Thanks.

Guess on my part, but I would think you have a shorted wire somewhere. Again, a guess, but would think that age, a wire (maybe on the underside of the truck) making contact with the frame has lost it's insulation and is now sitting bare wire to metal.

Or what FT said..

I have a 1989 GMC Sierra C1500. Recently, all my rear lights died, tail lights, brake lights. Also the inside dash panel lights died. These did all work until recently. I have replaced all the fuses, and all the bulbs, and nothing. Anyone have any ideas of what could be causing this?

Thanks.

My guess is a bad connector, open at the main light switch.

My 2000 Sierra has 2 panels, the main fuse assembly under the hood, and another access panel with relays in the dash. Open the driver's door and look for an access panel on the end of the dashboard facing the door. Pop it open and check the relays.

I have replaced all the fuses, and all the bulbs,
Thanks.
Stupid question.
Did you check if the old fuses and bulbs are still good?