Tail Light Issues
Tuned
Joined: Sep 2014
Posts: 454
Likes: 92
There are several ground points on the 1980. One in each tailight pocket and two on the the frame.
I had this issue as well.
I combined all the grounds (tail lights, license plate lights and pocket grounds into one wire run to the cab and terminated.
I had this issue as well.
I combined all the grounds (tail lights, license plate lights and pocket grounds into one wire run to the cab and terminated.
FTE Legend
Joined: Nov 2015
Posts: 30,831
Likes: 4,096
From: Angier, NC
There is 1 connector under the master / booster by the frame rail. The other is out back as King said left rear frame rail.
I know of the 1 from battery to motor / starter were the cable has a tab that bolts to the frame rail but that is all I know of.
Also the 80-82 truck don't seam to have the ground wire in the harnesses that terminated behind the radio. Neither of my 81 truck had this ground wire / connection and I did a full wire harness swap between the 2 trucks so I know.
The factory book is wrong on that ground wire for 80-82 trucks also.
Dave ----
Freshman User
Joined: Jul 2020
Posts: 42
Likes: 0
I have an 82 and and mine has the ground behind the radio that comes out of the harness. Today I put my dash pad back in and before I did, I disconnected that ground from the dash harness and cleaned it up, reconnected It and put in the dash pad. It had two ground wires connected to a ring that was screwed into the metal dash support. Funny some have some don't.
FTE Legend
Joined: Nov 2015
Posts: 30,831
Likes: 4,096
From: Angier, NC
I have an 82 and and mine has the ground behind the radio that comes out of the harness. Today I put my dash pad back in and before I did, I disconnected that ground from the dash harness and cleaned it up, reconnected It and put in the dash pad. It had two ground wires connected to a ring that was screwed into the metal dash support. Funny some have some don't.
Mine is a late 80 making it a 81 and everything i worked on also is 81 parts.
Dave ----
Freshman User
Joined: Jul 2020
Posts: 42
Likes: 0
I found this thread because I was also having a ground issue. It was a little confusing for me to keep track of which lights were working with headlamps on and what was not working with them off. After cleaning the grounds in each of the taillights recess behind the lens, and cleaning both grounds in the engine compartment on the front fenders by the lights, they all worked fine.
Freshman User
Joined: Jul 2020
Posts: 42
Likes: 0
1982 f150 4WD custom with the 300 six banger. Yours doesn't have the tail light grounds too, besides the behind radio ground?
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Ford Super Duty: 5 Things Owners LOVE, 5 Things They LOATHE!
Joe Kucinski
Every 2026 Ford Truck Engine RANKED from WORST to FIRST!
Michael S. Palmer
The Best F-150 Deal of Every Trim Level (XL through Raptor)
Joe Kucinski
FTE Legend
Joined: Nov 2015
Posts: 30,831
Likes: 4,096
From: Angier, NC
My 81 style side had the grounds behind each tail light and none behind the radio.
My late 11/80 flare side also did not have the ground behind the radio and don't remember a ground wire in the harness.
I don't know how the tail lights were grounded as that part was all hacked up.
Dave ----
Laughing Gas
Joined: Feb 2010
Posts: 781
Likes: 8
From: Sanford, NC
My 1981 F100 was made in Oct. or Nov. of 1980. It has the ground location under the dash
beside the radio. I don't know about the grounds some have on the tail lights. Everything on
mine works OK so I have not looked for additional grounds for the tail lights.
beside the radio. I don't know about the grounds some have on the tail lights. Everything on
mine works OK so I have not looked for additional grounds for the tail lights.
FTE Legend
Joined: Nov 2015
Posts: 30,831
Likes: 4,096
From: Angier, NC
Dave ----
FTE Legend
Joined: Nov 2015
Posts: 30,831
Likes: 4,096
From: Angier, NC
I have not gotten out to re-check if I have that ground by the radio but being I pulled both trucks apart and put 1 together and don't remember one well?
Dave ----
1st Gear
Joined: Jun 2023
Posts: 1
Likes: 0
Did you solve your problem ? What was it
My tail lights don't work.
The blinkers work. And the brake lights work when the lights are off, but as soon as I turn the lights on the brake lights don't work anymore.
I checked the wires with a test light and there is power to the socket when the lights are on. However the bulb does not light up and the brake lights don't work even though there is power in the wires like their should be.
Can anyone help me understand why the wires have power like they should and the brake lights work but the tail lights don't work and when I turn the tail lights on the brake lights don't work?
Thanks for the help!!
The blinkers work. And the brake lights work when the lights are off, but as soon as I turn the lights on the brake lights don't work anymore.
I checked the wires with a test light and there is power to the socket when the lights are on. However the bulb does not light up and the brake lights don't work even though there is power in the wires like their should be.
Can anyone help me understand why the wires have power like they should and the brake lights work but the tail lights don't work and when I turn the tail lights on the brake lights don't work?
Thanks for the help!!