Rear lights ground question
Laughing Gas
Joined: Dec 2017
Posts: 879
Likes: 40
From: Greensburg, IN
I'm chasing down the same symptom, somewhere there's a short in the circuit for the rear tail lamps. I do not see a ground following the harness from the left rr housing down across inside the bumper. Nothing is pinched, chaffed, or broken. Is it worth looking next at the switch on the brake peddle and work back from there?
2003 Excursion, EB edition.
2003 Excursion, EB edition.
This symptom is indicative of a short to ground:
Turn signals light up and pulse the third brake light and license plate lights
Hotshot
Joined: Jan 2004
Posts: 19,762
Likes: 1,079
From: St Louis
I'm chasing down the same symptom, somewhere there's a short in the circuit for the rear tail lamps. I do not see a ground following the harness from the left rr housing down across inside the bumper. Nothing is pinched, chaffed, or broken. Is it worth looking next at the switch on the brake peddle and work back from there?
2003 Excursion, EB edition.
2003 Excursion, EB edition.
Junior User
Joined: Jul 2005
Posts: 60
Likes: 0
In my experience (granted: on GM cars, not on excursions), these symptoms are usually caused by a hot-side short between tail and brake light circuits, or a short to ground, not strictly a ground issue. This is most often an internal short in the light socket, a failure of the light bulb itself, or in one instance, an improperly installed bulb that had crossed both contacts in the socket.
This symptom is indicative of a short to ground:
Easy way to check the common ground wire is to put it in reverse with the ignition on, engine off, and see what else comes on besides the BU lamps.
This symptom is indicative of a short to ground:
Easy way to check the common ground wire is to put it in reverse with the ignition on, engine off, and see what else comes on besides the BU lamps.
Laughing Gas
Joined: Jul 2018
Posts: 816
Likes: 7
From: Prescott, AZ
People go into the auto parts store and grab the wrong bulb, somehow manage to cram and bungle it in there, then wonder why everything goes wonky.
Laughing Gas
Joined: Dec 2017
Posts: 879
Likes: 40
From: Greensburg, IN
I've seen and repaired this too many times... most recently on a Jeep Liberty that the dealer wanted to charge the lady $260 plus labor to replace the taillight housing. Simply the wrong bulb crossing both contacts.
People go into the auto parts store and grab the wrong bulb, somehow manage to cram and bungle it in there, then wonder why everything goes wonky.
People go into the auto parts store and grab the wrong bulb, somehow manage to cram and bungle it in there, then wonder why everything goes wonky.
Junior User
Joined: Jul 2005
Posts: 60
Likes: 0
Reverse, brake and parking bulbs are good, sockets are tested good. I followed the entire harness from tail lights to interior and no where did I find chaffing or wear. The rear bumper is rusted out and can see and follow the rear harness across inside the bumper every thing is 100%. This sucks.
Laughing Gas
Joined: Dec 2017
Posts: 879
Likes: 40
From: Greensburg, IN
Reverse, brake and parking bulbs are good, sockets are tested good. I followed the entire harness from tail lights to interior and no where did I find chaffing or wear. The rear bumper is rusted out and can see and follow the rear harness across inside the bumper every thing is 100%. This sucks.
If you don't have any hotside shorts to ground, check for continuity between all your hotside contacts and the hotside of your parking lamps.
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Hotshot
Joined: Mar 2011
Posts: 11,950
Likes: 5,076
You might have been able to save yourself quite a bit of trouble by replacing that pigtail. It sounds like it could have been a bad connection between the bulb and the socket. A $10 part would have been easier....
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