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I am just now re-activating my account here, having been a member over 10 years ago, but having personal issues, I sort of drifted away; however, I still have my 77 F-150, but have significantly restored the pickup, and now am stymied with several electrical issues which have arisen nearly simultaneously. Having spent many hours already trying to find the problems, I now am asking for help! Please see below and tell me what may be my problems, and more hopefully, what do you suggest as a solution...
1. My headlights fail intermittently, after a few minutes of activation, but if I switch between high and low beams, the lights return - I have replaced both the dimmer switch on the floorboard, as well as the headlight switch up in the dash, but the problem keeps returning...any ideas?
2. I just replaced the turn signal cam which had a broken arm preventing the turn signal from automatically shutting off after a turn, but the replacement cam fit terribly, so I had to do some bending and cutting to make the prongs properly align; however, now after a short period of working properly, I no longer have rear turn signals - the front signals flash correctly, but nothing in the rear...any ideas?
3. About the same time as in #2 above, I noticed my brake lights no longer illuminated; I have bypassed the switch to isolate that potential problem, but the switch operates correctly...I also confirmed I do not have a wire issue by bypassing the switch with a confirmed power source, which did cause the brake lights to illuminate. Therefore, the problem seems to be the power to the brake light switch, which upon examination appears to disappear into the upper dash behind the speedometer...any ideas?
By the way, I have double and triple checked all fuses, with negative results, and the emergency flashers work fine...any help would be greatly appreciated!!
Welcome back around. As far as the headlight issue, even though you replaced the headlight switch, the headlight switch is internally fused and it sounds like that could be the problem. Now days alot of replacement parts are known to be bad over seas re-produced parts. I'd start there with installing a FOMOCO switch. Number Dummy should be right along and post up the part # and locations of who has one. Also check all grounds them and re-clean and re-attach.
T/S issue, maybe the bending and cutting to make things fit has broke off something inside? Maybe a wire has came off in the switch going to the rear? Sounds like you did a good bit of troubleshooting. Any sign on a wiring harness of a mouse chewing on anything up under there? Has a wire harness contacted a tail pipe or exhaust manifold? Yes sound weird, but things I ck for first. And again ck the tail light grounds back in the bed.
Thanks for the tips; I'll be back under the dash later tonight, as well as into the steering wheel housing looking for damaged wires - Ford sure could have given us a bigger housing for all the guts in the steering wheel!
Thanks, but no nicks as the cam sits above everything else, hence no bundle to pull down the tube, but Ford sure could have made the column housing with a wider diameter! Also, all of the turn signals worked for a couple of weeks before I noticed the rear signals no longer worked...
I'm not sure if this will help but my 74 F-100 had similar rear lighting problems. I got pulled over by the CA highway patrol, on my way out of the state because my back-up lights were blazing brightly while iI was going down the highway! After a coupke of hours of tracing wires, I found a spot roughly a foot forward of the rear tire, inside the frame, where the wire bundle had almost completely melted together. There was no heat source anywhere near this area, and it was well insulated. After separating each wire from the melted mess, and cleaning and reconnecting each on individually, then putting split plastic conduit around it, I have not had another problem since. That was 1994. My point is, you may want to check your wire bundle all the way back for breaks, exposed wiring, or cracks in the insulation. Hope any of this helps. Good luck!
Thanks for all the tips so far - I now have everything working except the right rear brake light - I have confirmed all is in order from the bulb to it's green power wire that runs up the driver side frame rail and up into the engine compartment, disappearing into a bundle of wires that enters the firewall into the cab area behind the dash...does anyone know how the wires are routed from there without trying to decipher the wiring diagrams? I'm about at my limit in working electrical problems!!
P.S. The right blinker works, which uses the same filament in the bulb as the brake light...
P.S.S. For anyone wondering about the headlight issue, it turned out to be a broken blade in the dimmer switch that was making intermittent contact...in years past the same problem was caused by the headlight switch in the dash, which had me going in the wrong direction from the start!
So how did you fix the other lights out back?
What you posted about the rear lights, brake & turns, all go thru the turn signal switch.
When you are on the brakes and have the turn on the switch stops the brake light from working so blinking on that side will work.
So when you have power in & out of the brake switch it then goes up to the turn signal switch and depending on what the switch is switched to will dictate what happens out back.
Now sometimes from sitting the signal switch contacts get a film on them and the lights stop working.
Sometimes you can spray the switch with an electrical contact cleaner and flip the switch a bunch of time and it will start working again.
If not replace the switch but I think the lights outback are a bad turn signal switch.
Dave ----
Thanks for the last tips - late last night I discovered Ford's stupid cost-saving measure of wiring the rear lights that way, to simply avoid adding a third bulb w/relay and wiring; as such, a cheap plastic crappy new replacement switch/canceling cam can easily result in an unsafe lighting problem that takes tons of time to diagnose...and once diagnosed, is a real pain in the a$$ to replace!! I was going to add a bunch more colorful metaphors last night, but decided to sleep on it...cheers!!
I had the problem fixed, then after I tucked everything back in the problem returned and I can't get the contacts in the correct position - do you know how the pins should be contacting the points in the different positions? Any tips would be appreciated!!
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