Ok, so when you turn the lights on, the in dash blinkers light up. This is very annoying. When you use the blinker it functions normally, maybe a little slow. Once you turn it off, the light in the dash, might get brighter, dim a little dim alot, be super brights, or go out altogether, and possibly randomly come back on in a little bit.

That is mostly true for the left one, right one for the most part stays on about the same brightness unless you use the blinker.

I have been told this is a grounding issue over and over and over and over....

I have double and triple everything including the park lights and the blinkers i know my grounds are fine, everything is grounded, i cannot stress this enough, do not just assume im an idiot and this is a grounding problem. trust me, my truck is well grounded. BTW, this did just happen overnight, well infact when overday? lol. I switched from a 79 to a 77 front clip. So my 79 has round headlights with the blinkers above them.

I figure it might be the blinker switch itself, but i cant find my steering wheel puller. If anyone has experienced this problem, i would love to hear from you, what worked, what didnt work and what caused it.

 

This happens on my truck from time to time. I have traced it down to the light bulb socket in the front - the ground wire makes a poor connection inside the socket. Maybe that's what is happening with your truck. Do you have a thermal flasher, or an electronic one? The stock flasher would act like the bulb was burned out, but the heavy duty electronic flasher I got for towing trailers flashes normally when this happens.

 

Hmm, that actually makes sense. as the right socket was a bit more corroded i suppose. I might have to look into new light sockets for the front. Just in case tho, im open to more ideas

 

Your problem is in the front. You have dual filament bulbs in the front, one filament is the parking light the other is the turnsignal. With a poor ground, the voltage from the parking light filament will go through that part of the bulb, and instead of going back to ground will search out another path and that happens to be the turnsignal filament in the same bulb. The voltage then runs up backwards through the wiring and lights the signal light in the cluster.

I know you don't want to hear it, but it is a ground problem. Now if you keep thinking a "ground" is a wire bolted to the body somewhere, then that's where you are mistaken. The dual filament bulb in the front is grounded through the brass base of the bulb, through the socket, through a plug and goes into the harness where it's grounded. Any of these places are susceptible to a poor connection, which would be a "bad ground" for that bulb.

Also during projects like this, some people want to "do it right" and paint everything up before they put it together. The paint affects the grounding. I am assuming you have scraped the paint away on the new front clip, and have a ground wire bolted to it going to the battery ground or another place that has a good ground.

 

I havent got around to the paint part yet, but when i put the diesel in i double grounded everything on both sides body to frame body to engine, engine to frame engine to body , frame to engine frame to cab frame to battery, each battery is grounded at the frame one both sides, new wires /connectors if needs, 36 grit wheels to do the cleaning. Basically every part of the vehicle is grounded to every other part twice, then batteries to frame on each side. I even put in a second ground for each blinker/prk light bulb right out of the socket on teh core support. Did not fix the problem, or even help for that matter.

So in essence with your help allow me to correct myself. It is a ground issue, just not a battery ground issue as most assume.

Indeed it does seem like it must be the sockets as those were the only thing changed. I wonder though, why does the left one sometimes go out after use of the blinker only to come back on later? Any chance the signal switch itself could cause this?
I have new turn signal / flasher relays as well, this helped my blinkers, but didnt fix the back feed problem.

 

Just take out the front bulbs, if it solve the problem it is the source of the feedback voltage.

 

bulbs out = no back feed.

 

The socket part of the light fixture is not getting a good ground or it is loose… and/or it is a loose and sloppy fit. Make sure the brass part of the bulb/socket is clean and shinny. If the bulb is loose in the socket try stuffing a wire down about 2/3 of the way down the side, between the bulb and the socket, use this as an EXTRA ground to help you troubleshoot the system.
I have always found it is just easy to keep adding grounding wires then trying to find the existing bad ground connection.
Good luck, you are getting very close to fixing this problem.
Jim

 

I don't know about the 79 sockets, but I do know both of the front sockets on my 1980 eventually failed, and it was the ground part. They were plastic, and for some reason the ground connection inside the socket would go bad. They have the metal tang that contacts the brass part of the bulb, and it goes down and there is another connection made down inside the plastic socket that seems to fail.

I replaced one complete socket and that fixed the problem on that side. On the other, I actually bypassed the original ground connection in the plastic socket, and soldered a new ground wire directly up inside the socket to the brass tang, and ran it down through and used it as the new ground for the socket, and it worked fine also.

 

Thanks again Dave, you have been an enormous help. I will take a better look at em tomorrow while trying to find out how bad my wiring got cooked... It didnt fry em from the inside, just melted em from the heat when it lit it seems... hopefully it didnt hurt anything that isnt being removed for the 3G swap, didnt appear to have on first glance but it was about half dark by then.

 

Well id like to thank you guys for the input. I was at the pull-a-part the other day and there was a 76 with the blinker marker and headlight harnesses just sittin there so i grabbed em up, for $5 cant really go wrong. Got em in, and no more constant blinkers!! I did notice the sockets on the ones i picked up were in considerably nicer and cleaner shape than mine, and they also have two wires going to ground as mine only had one. Scored a really nice cluster even that wasnt faded nearly as bad as mine with almost the same mileage even (1k less than mine).

And since im in the electrical thread, anyone know where and how i should tie in for my factory Alt. gauge to work? From what i understand it requires some sort of diode somewhere, (i assume the Alt, charge wire) to tell the gauge how much juice the alternator is actually putting out, rather than just reading the batteries.

 

I think most of the answers you need are in this thread.

https://www.ford-trucks.com/forums/1...t-located.html

Post 21 has a picture of the shunt. The 4 pin connector that is shown in the left of the photo is near the starter solenoid.

BUT wait ... do you currently have idiot lights... not gauges?

Jim

 

Negative, i have the Alternator gauge, NOT light.