Tail light wiring issue
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Tail light wiring issue
I was crawling around under my truck this weekend. I got no tail lights with the headlights on. My turn signals and brake lights work just nothing with headlights on. I traced the wiring from the plug by my master cylinder to the back. I didn't see any grounds or a spot for a ground for that matter.
I changed the headlight switch a couple weeks ago when it first happened but that didn't fix it.
Also which wire at the plug should I check to see if it has power to the back?
I changed the headlight switch a couple weeks ago when it first happened but that didn't fix it.
Also which wire at the plug should I check to see if it has power to the back?
Ford Parts Specialist
Joined: Nov 2006
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From: Simi Valley, CA
Same one piece molded plastic tail lamps & sockets:
1974 F100/350 Styleside from serial number T80,001 - 1975/79 F100/350 Styleside - 1975/91 Econoline - 1978/79 Bronco.
The Bronco & Econoline lamps have a foam rubber seal that can be peeled off.
1974 F100/350 Styleside from serial number T80,001 - 1975/79 F100/350 Styleside - 1975/91 Econoline - 1978/79 Bronco.
The Bronco & Econoline lamps have a foam rubber seal that can be peeled off.
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Not sure what this means?
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
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From: Simi Valley, CA
It means that all these vehicles use the SAME tail lights and sockets.
Valuable info if hitting junkyards. How many people would know that these parts are the same as Bronco & Econoline?
Valuable info if hitting junkyards. How many people would know that these parts are the same as Bronco & Econoline?
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Fleet Mechanic
Joined: Sep 2014
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From: NE Texas
Grounds
Electrical weirdness is often ground related. You probably have four ground points, two by the tail lights and two at the front near the headlights. (remember, your front lights are on the same circuit as the rear ). Check that you have a solid ground at each point, and that in each of the eight sockets you have a solid connection between the ground in the socket and the ground wire. Check your battery ground and engine grounds while you are at it. A whole lot of lighting issues stem from bad grounds, so if you eliminate that as a cause early, you save yourself grief later.
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Some help https://www.ford-trucks.com/forums/1...ml#post1812190
And even more help. Turn and Stop Lamp Diagnosis for 70's Ford Pickup - Ford-Trucks.com
And even more help. Turn and Stop Lamp Diagnosis for 70's Ford Pickup - Ford-Trucks.com
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From: spokane
I literally JUST went through this with my truck. I replaced the sockets and the problem was solved, but I also didn't come across an issue like your picture with the broken wire right off the plug.
I also added grounds from cab to chassis, bed to chassis, and bed to cab in addition to NEW grounds from block to battery, battery to chassis, and block to cab. I now have lights working (side markers on bed and cab clearance lights) that never worked before. Basically what I'm saying is refresh your grounds and it doesn't hurt to add more! Also just replace the sockets, they're super cheap.
I also added grounds from cab to chassis, bed to chassis, and bed to cab in addition to NEW grounds from block to battery, battery to chassis, and block to cab. I now have lights working (side markers on bed and cab clearance lights) that never worked before. Basically what I'm saying is refresh your grounds and it doesn't hurt to add more! Also just replace the sockets, they're super cheap.
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I wish the junkyard by me had some of these trucks so I can get what I need. Ill probably just try and find a new universal 8 pin connector, cut and solder it in. I will still go around and change all my grounds. My fuel gauge just stopped working today as well, and I'm willing to get it has to do with that connector or a ground. I drove my truck to work and noticed an empty tank, which is funny as I filled it up over the weekend.
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From: spokane
Obviously you need to fix the one broken wire on that connector, but I would still recommend replacing the bulb sockets. I'm not joking, I had the EXACT same symptoms (lights worked fine with head lights off, but nothing out back with headlights on) and I replaced the sockets because I broke a pin trying to clean the contacts and everything worked perfectly after new sockets.
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Well. I had parking lights and brake lights working good for awhile. I stopped for gas, and a guy pulled in and said my brake lights arent working. I got a new brake light switch. I really hope that fixes it.