Brake Light problem

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64 f100
Posts: 2754
Joined: July 18, 2006, 7:23 am
Location: Carmi, Illinois, 62821

Brake Light problem

Post by 64 f100 »

Everything was working as far as I know until two days ago. At least as far as I know. A friend stopped me and told me my brake lights were not working. Turn signals and tail lights were. So I figured the brake light switch, and put anew one on. That did not work so I checked brake fluid which was low, but not critical. Filled it and then jumped the two wires for the brake light switch to see if I could get lights that way, and still no lights. Pulled the wheel and inspected the turn signal for having overheated or if it had a burn spot. None to be seen. Pulled the wires loose at the plugs, and checked the functions against a new one. Functions seemed the same. Nothing seemed to be wrong there. I believe the problem is under the dash the 20 Amp fuse was blown so I replaced it. The wiring has had some custom wiring done, but nothing that looks like any real butchery was done. The light switch needs the nut tightened up, and I will do that tomorrow, but can't believe that would cause this kind of problem. Any thoughts as to what might be causingthis kind of problem or any specific things to look at? :(

Rich
64 f100
Posts: 2754
Joined: July 18, 2006, 7:23 am
Location: Carmi, Illinois, 62821

Re: Brake Light problem

Post by 64 f100 »

I forgot to mention that the 20 amp fuse has not blown since it was replaced. Surely someone has some idea on where to look for the problem. It has to be between the brake light switch and the tail light harness, and I feel fairly confidant that it is not in the turn signal switch, but I cannot rule that out as the source of the problem, as I do not know enough about how it supposed to work. The Ford repair manuals do not even have the schematics for the wiring. Takes a separate manual for wiring. Even then it's kind of a fit all covering all models, and not real specific to any given model.
William-in-St George
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Joined: December 31, 2009, 5:26 pm
Location: Saint George Utah

Re: Brake Light problem

Post by William-in-St George »

I would gently pull the firewall connectors, clean them and apply a little bulb grease. Usually these issues are related to the turn signal switch. You have already checked the obvious, jump the switch wires, replaced fuses and checked the tail light housing for a good ground. My nickel says it's the TS switch.
William-in-St. George
ICEMAN6166
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Re: Brake Light problem

Post by ICEMAN6166 »

64 f100 wrote: and then jumped the two wires for the brake light switch to see if I could get lights that way, and still no lights. Rich
has to be 12v coming out of one of the wires for that to work, key needs to be on or jumped directly from 12v.

had one once where the wire in the column tube had rubbed bare and was grounding out. took a long time to chase that one down :cussing:
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64 f100
Posts: 2754
Joined: July 18, 2006, 7:23 am
Location: Carmi, Illinois, 62821

Re: Brake Light problem

Post by 64 f100 »

Well, I found the problem and the problem belonged to the nut behind the wheel. I recently went thru my steering column and redid it from top to bottom, including the turn signal switch. Somehow, I switched two wires when reinstalling the plug. This has been some while ago and I've been all over the place with the truck. This has been at least a month or so ago when I worked the column, and finally someone let me know the brake lights were not working. I had traced the problem to the turn signal switch and isolated the problem, and I then noticed the wires on the plug in did not appear to be right. I had the brake light hot wire coming to the horn. If I had the horn working I might have noticed it before, but the little contact was not in the column, so noting happened when I pushed the horn ring. Thanks for the advice and help. I just spent a couple days pulling my hair out trying to figure out where the problem was. Like I said it was the nut behind the wheel.
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