I have a 89 gmc surburban I have no rear running lights or light around the licence plate. All other lights workin the rear. I did not have a blown fuse replaced the light bulbs as well. Thinking it was the light switch itself i change it but no good. please help

Could be wiring check for power at the connector under truck by rear bumper

As danielroth said above, check the junction point. I cut the whole thing out on my '92 and installed a 7 stud connector box for a trailer re-wired the lights to the box, wired the truck harness to the box, added the trailer brake controller wiring and added a new 7-way wire for my trailer plug. I made sure I used the correct grommets on the box then filled it with di-electric grease. Not a problem since and if there was it would be easy to find.. If the junction is fine check the wiring up to the front of the truck it may be damaged.

where exactly is the junction point?

Behind the rear bumper. Since I had a truck I could lower the spare to work on it. You are not so lucky, the fuel tank will be in the way.

Thanks for all your help fixed the problem yesterday it was a broken wire right underneath the drivers door someone had spliced the wire and it had broke.the pice shows the culprit