2007 gm sierra right running tail light will not work left one is fine

If after checking the bulbs are ok then the fuses could be suspect!

Has to be a grounding issue,look for a chassis ground from the
back harness,pretty weird symptom

Same thing was wrong with my 95 gmc it was tail light assembly that bulbs plug in to 15dllars eBay or 68 dollars at dealer ?!!!

replace the bulbs in the tail light, they are 2 stage, one for parking light and one for brake/signal

sounds like you may have a hitch installed on your vehicle and the ground wire between it and the taillight is damaged. if it doesnt have a hitch the most likely cause is still a ground at the rear of the truck on the frame rail drivers side where the factory wiring is located for the trailer plug. this is a common issue. i hope this helps

You have a bad ground to the rear lights. It is on the drivers frame rail.

One wire is for the brake/directional filament and the other wire is for the tail light. The fixture should be grounded when it is attached to the bracket. To test which is which (the brown wire is USUALLY the ail light) make sure the fixture is grounded and touch a hot wire to each of the wires coming from the fixture. Watch to see which wire lights up the brighter filament and this is the brake/directional light. The dimmer filament if the tail light. Brakes lights and directional lights are both the same filament. Wen the brakes are applied, both lights are activated. When a direction light is turned on, it simply flashes the brake light filament.

lower the tail gate and remove 2 screws at the top and bottom of the lamp that you swant to remove then pull lamp towards the rear of the vech.
The lamp should come out.

The fuse you are looking for should be in the middle of the fuse box and is marked instrument cluster. Chances are that it is good. On a GM if the tail lights and dash lights go out at the same time that is a sure sign that you need a new headlight switch. Hope this helps.

back feed causing the brake light to ground off of the head lights caused by bad ground or possible short