Electrical Problem
Thread Starter
1st Gear
Joined: Jun 2011
Posts: 1
Likes: 0
Electrical Problem
I just got through restoring a 1971 Convertible. As part of the restoration all new wiring harnesses were purchased and installed. The problem I'm having is with the passenger tail light burns dim when the running lights are on and goes out when you apply the brakes. I'm leaning toward a ground issue but don't know where to begin looking.
Any thoughts or opinions are greatly appreciated.
Any thoughts or opinions are greatly appreciated.
Burning Brakes
Joined: Feb 2009
Posts: 780
Likes: 1
From: Shelby NC
Hope you have a good test light you need to check your ground system for a feed back coming from somewhere. I have had the filament in a blub break and fall down on the other filament in a blub and cause all kinds of problems.
Good luck--you should find it OK.
Good luck--you should find it OK.
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,847
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
I just got through restoring a 1971 Convertible. As part of the restoration all new wiring harnesses were purchased and installed. The problem I'm having is with the passenger tail light burns dim when the running lights are on and goes out when you apply the brakes. I'm leaning toward a ground issue but don't know where to begin looking.
Any thoughts or opinions are greatly appreciated.
Any thoughts or opinions are greatly appreciated.
You should also check the grounds and while your at it, check the parking lamp extension plugs.
Willcox
Le Mans Master
Joined: Nov 2001
Posts: 8,571
Likes: 1,847
From: LONG ISLAND
2025 C3 ('68-'73) of the Year Finalist - Unmodified
2024 C3 of the Year Finalist - Unmodified
2023 C3 of the Year Finalist - Unmodified
Mine go dimmer when I hit the brake pedal sometimes & the battery gauge bounces as well.
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,847
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
I have an isolated schematic of the 68-72 system on my office computer.. I think I'll put this up tomorrow on the help repair side of the site and post it. It really makes this easier to diagnosis.
Pro
Joined: May 2011
Posts: 581
Likes: 5
From: BC
You are almost certainly dealing with a ground issue. While there are other possibilities, they would be the exception. Confirm it by using a jumper wire attached on one end to a known good ground. Touch it to the bulb socket exterior. If your light intensity increases it' a confirmation. Simply follow the harness ground circuit back with your jumper until you locate the resistance.
Steve
Steve
Safety Car
Joined: Sep 2007
Posts: 4,443
Likes: 326
From: Indy Indiana
your frame is a known good ground, run a wire form your taillight housing to the frame.
another problem may be your harmonica connection at your feet/steering column may be barely making contact, or your connection of your firewall harness to the rear harness ( at your left foot by the dimmer switch), may not have a good connection.
I had a similiar problem and the connection showed 12 volts, but would not pass the required current and not light the bulbs, cleaning all the contacts at these harness connections solved my problem.
another problem may be your harmonica connection at your feet/steering column may be barely making contact, or your connection of your firewall harness to the rear harness ( at your left foot by the dimmer switch), may not have a good connection.
I had a similiar problem and the connection showed 12 volts, but would not pass the required current and not light the bulbs, cleaning all the contacts at these harness connections solved my problem.
