All rear lights not working

1992 GMC SONOMA
199,000 MILES • 4.3L • 6 CYL • 2WD • AUTOMATIC
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BCRRHI1951
  • MEMBER
  • 1 POST
Headlights work. I have no lights in rear at all.
Nov 9, 2020 at 2:40 PM
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JACOBANDNICKOLAS
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 110,190 POSTS
Hi,

If nothing in the rear works, signals, brake lights, parking lights, the one thing I see they all have in common is they use the same grounding point. What I need you to do is check the black wire on either side for continuity to ground. I attached one pic below. Each system has a different schematic (signals, brakes, tail lights) but they all show the same ground.

If you find there is no continuity to ground, as a test, run a new ground and attach it to the black wire to see if the lights start working.

Let me know what you find or if you have other questions.

Take care,
Joe
Nov 9, 2020 at 8:14 PM
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