I have a 1979 f100 300I6 that the revers lights stays on . I have no side lights
And license plate light and no insterment lights to see the gauges at night.it seams to be in the back .because the front lights work.front side lights work.
Cab light works,head lights work,blinkers work.has any one had this problem before .and do you think the reverse light socket is bad and would it effect the rest of the light. Thanks for your advise.

 

I'd start working on grounds first thing. Run a new ground from body-frame, engine to body, bed to frame, etc. grounds are the first thing to go on these trucks and make lights do strange things. Also look for previous hacks in wiring. Have the rev lights always been that way or just recently?

 

IT was that way when I bought it.so he took 200.00 off the price.what he did was take the bulb out of the socket .but I drove to the cvs and got pulled.i forgot he did that. Luck the bulbs Wher in the glove box.so I just put them back in and drove home .i left them in and let them burn during the day.just in case I drive at night.i hate taking them out putting them back in.

 

if your truck is an automatic then the NSS switch may be bad as well, and there will be a jumper wire in a weird plug under the hood on the driver side of engine bay. the jumper plug will keep the reverse lights on all the time when the ignition is on

 

My truck is a 3 on the tree with revers .

 

Well my side lights work and one blinker works the left turn signal.but the right just lights up but does not blink.i guess when I went under the dash and played with the fuse the side
Markers came on.this is strange.i hate electrical problems.

 

Well my side lights work and one blinker works the left turn signal.but the right just lights up but does not blink.i guess when I went under the dash and played with the fuse the side
Markers came on.this is strange.i hate electrical problems.

 

Wireing and Electrical can be a pain in the ****. But sort out every gremlin and snafu, and the opposite of Murphy's Law, Yhprum's Law comes into effect. With everything accounted for, it should work.

Check for corrosion on the contacts, and clean them as much as possible. Check for overheated or burnt wire insulation, which can be caused by corrosion, and replace the wire and connector. Every terminal can be removed from the electrical housing using a small jewelers screwdriver and you can clean them up thise way. Once satisfied you can protect the contacts with dielectric grease, which I use everywhere on all contacts.

Eventually, if you do this right, you can shake a harness and wiggle stuff without anything burning up or loosing contact.

Maybe hit youtoob and see if there are any videos about diagnosing electrical, and familiarizing yourself on the multimeter and how to use it to sort this crap out. Whatever you do, do not use crimp connectors without sealing the wires up! I like using the heat shrink with solder in it for my field repairs, as all I need is a lighter and burnt fingers.

If it helps, I spent two years working on my harness for the EFI I stuffed into my '78. I built it over kill using what I learnt from the OEM's to keep water out and electricity in

Hope this help with encouragement and to not give up!

If you do, buy a new harness and spend big bucks...

edit: The lamp sockets are not the best sockets in the world. You can buy exact replacements from cheap auto parts stores, but the best is to upgrade to the newer design from the bullnose trucks ('80's era).

 

Is it easy to take off the fuse box under the dash.and should I take out all fuses when taking out the fuse panel? And thanks for the conference.

 

If you think there is a loose connection there, go ahead and pull the fuse panel to clean and fix it.

But, before you do pull the leads off the Battery! Then no worries about shorting to ground and making some ashes...

 

Well thanks for the advise .i went to Autozone today and bought a 6-12 volt circuit tester
To check all my leads and wires going to and from the turn signal. I also set up an appointment for tomorrow at Goodyear to have new shocks replaced.

 

I had a truck that the fuse panel was so badly corroded inbehind that we had to replace the fuse panel, took out every wire and plugged it into one we got from a wrecker

fuse panel is easy to pull, just 2 screws hold it onto firewall under dash

good idea to put the correct size fuses in, the heater is a 30Amp fuse and i've seen so many of these trucks with a 20Amp fuse in them and the PO was wondering why the blower motor turned so slowly, replaced with 30A and blower moves that air!

same with the starter solenoid and hazard lights, if there are iffy fuses or wrong size fuses or corrosion on where the fuse sits there can be weird problems.

also with the front lights, if the hazard flasher or turn signal flasher is weak or dying the lights will act funny

also with the front turn signal lights each side has a ground wire to the front of the rad support underneath the rubber pieces that are cliped to the rad support and the grille shell.

and the aftermarket replacement sockets can have different color wires, I had one 2 days ago, white doesnt go to white and black doesnt go to black, what was it again, white(with stripe) to red, and brown to black, and black to white. - white-brown-black is truck side and red-black-white is new replacement socket, if it is wired differently then the side running lights will blink with the turn signals and will blow the hazard flasher under the dash, how do I know this? lol I'm pretty sure that is how I ended up wiring in that new socket

 

Let me tell you this truck to be a79 it's cherry no rust at all.i looked under the truck last night and I thought it was a littel dirty but that can be cleand.but as far as every thing else
This truck can be bought back to looking like it just drove off the show room floor.i just have to figure out my electrical problem .with the help from you nice fellows I will get it done.its just going to take time.because I am a littel tight on money right now.