Tail lights.
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New User
Joined: Mar 2005
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Tail lights.
1972 F100. Both tail lights are out.
Blinkers on-front lights come on but do not blink.
Hazards-Fronts come on but do not blink.
Brakes-rears do not come on.
Backups-work.
Any help?
Milton
Blinkers on-front lights come on but do not blink.
Hazards-Fronts come on but do not blink.
Brakes-rears do not come on.
Backups-work.
Any help?
Milton
Cargo Master
Joined: Jul 2003
Posts: 2,328
Likes: 14
From: Colorado
Have you messed with your turn signal cancel cam? I know that if it's not JUST right then the blinkers will not work correctly. Turn signals will come on but not blink etc. I had problems when I redid my cancel cam, but I got it worked out. Just somethin' to check.
Fleet Owner
Joined: Jun 1999
Posts: 24,552
Likes: 74
From: Creedmoor, North Carolina
About the only way I know to troubleshoot your problem is to start at the light housing with a test light and start working forward to the dash. There are 3 wires that come to be rear (4 if you have backup) brown, yellow, & green. Tails are used by one and brake/turn signal by the other two. You can start at the housing and then unplug the connector at the rear of the bed test it and go from there. Don't to forget to check fuses, sometimes a chafed wire can short and blow them.
John
John
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Post Fiend
Joined: Jun 2002
Posts: 13,873
Likes: 3
From: Atlanta GA
Start at the fuse box, then replace both flashers with at least a HD (557?) flasher. Make sure power is going through the flashers and through the flasher switch and turn signal switch (by testing on the firewall side by disconnecting the harness under the hood) before you even start with lamps.
Many lamps problems are pretty simple, a bad ground or bad socket. You only have four wires going to the rear lamps (left right brake/parking reverse). If you have power going to the rear then you know it is most likely a ground problem.
You can buy new sockets to splice in at NAPA if it is the sockets.
Many lamps problems are pretty simple, a bad ground or bad socket. You only have four wires going to the rear lamps (left right brake/parking reverse). If you have power going to the rear then you know it is most likely a ground problem.
You can buy new sockets to splice in at NAPA if it is the sockets.
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speaking of lights
Post Fiend
Joined: Jun 2002
Posts: 13,873
Likes: 3
From: Atlanta GA
> I don't have backup lights but the bulbs work, what should I check?
Disconnect the harness under the hood, put 12v to the back up lamps from a -> fused <- test lead and see if they light up. If they do, then check the harness that goes from the transmission reverse switch.
Many times the harness is good, the switch is bad, because the little roller ball inside the switch goes bad after being used 50,000 times in 30 years.
Use the fused lead to put power into the harness and see if you get power out while the truck is in reverse with the engine off/key on/parking brake on. The 12v will make a complete circuit into and out of the harness if everything is good. That way you avoid removing the rug and floor to get at the switch.
Disconnect the harness under the hood, put 12v to the back up lamps from a -> fused <- test lead and see if they light up. If they do, then check the harness that goes from the transmission reverse switch.
Many times the harness is good, the switch is bad, because the little roller ball inside the switch goes bad after being used 50,000 times in 30 years.
Use the fused lead to put power into the harness and see if you get power out while the truck is in reverse with the engine off/key on/parking brake on. The 12v will make a complete circuit into and out of the harness if everything is good. That way you avoid removing the rug and floor to get at the switch.
Cargo Master
Joined: Sep 2004
Posts: 2,691
Likes: 6
Originally Posted by SpankF100
I don't have backup lights but the bulbs work, what should I check?
New User
Joined: May 2004
Posts: 6
Likes: 0
From: Omaha
Just a guess all but what about the neutral safety switch. Just had some steering column work done and the guy said that that switch is linked to the back up lights somehow. Havent worked on it since but I would be interested to know if the guy was fos.
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New User
Joined: Mar 2005
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Well, the previous owner had installed a plug to run his boat trailer lights, and it was gone. I must have ran over something, as most of the wiring in the rear of the bed was cut/torn out. I used my multi-meter, and about 6 splices, and now all of my lights work as advertised.
Thanks for the help. I do need to replace the turn signal switch, as the right blinkers do not shut off automaticaly. My 72 year old Dad confirms these switches are a POS.
Milton
Thanks for the help. I do need to replace the turn signal switch, as the right blinkers do not shut off automaticaly. My 72 year old Dad confirms these switches are a POS.
Milton