Wiring issue???
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Wiring issue???
i just bought a 1980 f150 with a 86 frame and this truck has a wiring issue I just can't figure out. The truck starts and runs fine, but if the lights are on you can't shut the truck off with the key. As soon as you shut the lights off the ignition works fine. Any ideas on what could be going on??
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The headlight switch and associated wiring are frequently the cause of problems. Check out the headlight switch and the wires connected to it to see of the wires are melted. If. So one may have shorted with the ignition wire. You can see the schematics here: 1981 EVTM - ???Gary's Garagemahal.
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Another experiment you can try; If you have some jumper cables, hook one end to the negative battery cable and hook the other end to a place on the radiator support that you can get a ground. See if that makes any difference.
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I don't think that's the issue, I replace all the cables from the battery to the starter solenoid to the battery and from the battery to the engine to the frame to the rad cradle Because I also thought that might of been the problem
I also pulled the harness from under the hood to the tail lights and fixed any broken wires thinking that might of been the problem but it wasn't
I also pulled the harness from under the hood to the tail lights and fixed any broken wires thinking that might of been the problem but it wasn't
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If you do not think it's a ground, then it will have to be 12v crossing over somewhere like Gary said. He is also correct, the tan/white that feeds the running light circuit to the headlight switch likes to overheat and melt.
If you want to test the tan/white melted wire theory, take the running light fuse out, then see if the problem goes away. Of course your running lights won't work like this but you will have a good clue as to where the problem is located. Your headlights should still work with this fuse out.
If you want to test the tan/white melted wire theory, take the running light fuse out, then see if the problem goes away. Of course your running lights won't work like this but you will have a good clue as to where the problem is located. Your headlights should still work with this fuse out.
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Freshman User
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The headlight switch and associated wiring are frequently the cause of problems. Check out the headlight switch and the wires connected to it to see of the wires are melted. If. So one may have shorted with the ignition wire. You can see the schematics here: 1981 EVTM - ???Gary's Garagemahal.
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Freshman User
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If you do not think it's a ground, then it will have to be 12v crossing over somewhere like Gary said. He is also correct, the tan/white that feeds the running light circuit to the headlight switch likes to overheat and melt.
If you want to test the tan/white melted wire theory, take the running light fuse out, then see if the problem goes away. Of course your running lights won't work like this but you will have a good clue as to where the problem is located. Your headlights should still work with this fuse out.
If you want to test the tan/white melted wire theory, take the running light fuse out, then see if the problem goes away. Of course your running lights won't work like this but you will have a good clue as to where the problem is located. Your headlights should still work with this fuse out.
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I'm checked every wire in the truck and I didn't see anything that was melted, rubbed threw or broken. All I have left to do is start replacing switches I guess. I had to order the light switch, it should be in tomorrow. Anyone have any other ideas?
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So I changed the light switch and now I can shut off the truck with the lights on, but I found another issue. When the truck is running the marker lights are dim. If I turn the key just a little bit the lights get bright. Could I have a faulty ignition switch or could something be wore out?
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From: Virginia
The ignition switches are bad for not sitting in the right place and also getting wore out. I would replace the ignition switch. Hint: It's under the dash.
Take the cover off the column near the cluster
Disconnect the little tube with the string in it that works your PRND21 indicator
Take the two bolts out on the u-clamp that holds the column to the dash
Drop the column down and let the steering wheel sit on the seat. You can then see and get to the ignition switch
I would also spray a little wd40 into the key mechanism so it works freely.
Take the cover off the column near the cluster
Disconnect the little tube with the string in it that works your PRND21 indicator
Take the two bolts out on the u-clamp that holds the column to the dash
Drop the column down and let the steering wheel sit on the seat. You can then see and get to the ignition switch
I would also spray a little wd40 into the key mechanism so it works freely.
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From: Northeast, OK
Thread Starter
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Freshman User
Joined: May 2017
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So I changed the light switch and now I can shut off the truck with the lights on, but I found another issue. When the truck is running the marker lights are dim. If I turn the key just a little bit the lights get bright. Could I have a faulty ignition switch or could something be wore out?
The ignition switches are bad for not sitting in the right place and also getting wore out. I would replace the ignition switch. Hint: It's under the dash.
Take the cover off the column near the cluster
Disconnect the little tube with the string in it that works your PRND21 indicator
Take the two bolts out on the u-clamp that holds the column to the dash
Drop the column down and let the steering wheel sit on the seat. You can then see and get to the ignition switch
I would also spray a little wd40 into the key mechanism so it works freely.
Take the cover off the column near the cluster
Disconnect the little tube with the string in it that works your PRND21 indicator
Take the two bolts out on the u-clamp that holds the column to the dash
Drop the column down and let the steering wheel sit on the seat. You can then see and get to the ignition switch
I would also spray a little wd40 into the key mechanism so it works freely.