Electrical problems on a 79 f100?
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Electrical problems on a 79 f100?
I have a 79 F100 the electrical is all to hell .the right side turn signal is week.the left works right the reverse light stays on the dash lights do not work the back running lights do not work. The only lights that work are the break lights the inside Dom light works the head lights work and the front running lights work .some one said its a common problem with older ford trucks. Well my problems is wher to find a garage that will fix the problem.can I have them just run new wires from each of the problem lights and hook up to the fuse box or just take all the wires out and run all new wires?
Moderator & parts slinger
Joined: Feb 2007
Posts: 50,188
Likes: 5,792
From: S/W Missouri, Polk county
Sounds like maybe a bad headlight switch and a bad turning signal switch. Ck all fuses and bulbs. Clean all the grounds and elec connections where the bulbs go in. Ck the wiring harness going down the inside of the dvrs side frame rail for rubs, chaff, exhaust burn marks. Ck the back end of the harness for a PO added in trailer hook up. Some times that can cause problems.
Reverse lights stay on, sound like the NSS switch needs adjusted, down on the side of the transmission.
No dash lights, do you have the headlight switch rotated all the way to turn the dash lights all the way up? CC I believe and to the notch just before you turn on and lock on the dome light on. It could be bad bulbs, but ALL of them? Does the light behind the headlight/wiper switch come on?
Come here and read this: https://www.ford-trucks.com/forums/1...ml#post1812190
And make sure you read this one too. https://www.ford-trucks.com/article/...rd_Pickup.html
Reverse lights stay on, sound like the NSS switch needs adjusted, down on the side of the transmission.
No dash lights, do you have the headlight switch rotated all the way to turn the dash lights all the way up? CC I believe and to the notch just before you turn on and lock on the dome light on. It could be bad bulbs, but ALL of them? Does the light behind the headlight/wiper switch come on?
Come here and read this: https://www.ford-trucks.com/forums/1...ml#post1812190
And make sure you read this one too. https://www.ford-trucks.com/article/...rd_Pickup.html
Laughing Gas
Joined: Mar 2015
Posts: 885
Likes: 2
From: Pittsburgh
77&79 has the best idea for what to check first before blowing it out of proportion.
But don't let some shop butcher up your wiring more if its going to come to that. If you need more than 1-2 new wires and you can't do it yourself, go with the full new wiring harness. I'm almost there in my list of projects as well. Its an expensive one but I've seen numerous "electrical dummies" on here that all say the same thing..."Glad I saved the money and did it myself".
Replacing only what you need will just become more and more expensive as time wears on...its 35+ years old for goodness sake.
But don't let some shop butcher up your wiring more if its going to come to that. If you need more than 1-2 new wires and you can't do it yourself, go with the full new wiring harness. I'm almost there in my list of projects as well. Its an expensive one but I've seen numerous "electrical dummies" on here that all say the same thing..."Glad I saved the money and did it myself".
Replacing only what you need will just become more and more expensive as time wears on...its 35+ years old for goodness sake.
Post Fiend
Joined: Apr 2002
Posts: 19,311
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From: Waterloo, Iowa
Use your voltmeter and perform a few simple procedures. Follow the instructions linked and you'll be as good as whoever you take it to, if maybe not so quick on the draw but it won't cost anything but your time.
Get all new ground and battery cables. Trust me. Grind down to bare metal the connection points at block, frame, and firewall. Tighten securely, coat with grease, NO-OX, etc.
Clean shiny connections = Happy electrons
http://www.aa1car.com/library/voltage_drop_testing.htm
Get all new ground and battery cables. Trust me. Grind down to bare metal the connection points at block, frame, and firewall. Tighten securely, coat with grease, NO-OX, etc.
Clean shiny connections = Happy electrons
http://www.aa1car.com/library/voltage_drop_testing.htm
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