78 F350 Electic issue....

rusty ol ranger · Jul 22, 2009

Ok, here it goes...

I pulled the box off and replaced it with a flatbed...

I plugged in magentic towing lights into the Towing plug, left the stock taillight connecter unhooked.

I have no tailights or turn signals. I have brake lights, dim ones, but they work. The turn signals work, but when you turn on the left or right one (doesnt matter) both back lights flash like the hazards are on. The front ones work fine though, and taillights are non existent.

I cant remember if they worked before i pulled the box off or not, its been like a year, the damn thing mainly just sits here.

My question is....does the taillight harness need to be grounded for the towing lights to work? Also, what would cause both of them to flash like the hazrds are on? A bad ground?

I am also thinking it Might be in my 7-4 light adpator. The truck has a 7 prong RV style plug, my magentic lights have a 4way so i used one of those adaptors, which i also used on a car hauler trailer and the trailer did the same thing as the truck is doing.

Help please...electic is not my strong point....

later,
Dustin

BRUTUS_T_HOG · Jul 22, 2009

your trailer plug must have a bad ground or a bad connection.. try to provide a good ground with a jumper wire and see what happens.. i think the white wire of the trailer harness is ground

martin · Jul 22, 2009

The wiring in the adapter is incorrect. There are diagrams for this somewhere on the net, I found them about a month ago but can't remember where. The easiest thing to do is to just trace them through. Can't remember what the protocol is for the seven or eight pin end but the four pin goes ground, lights, left, right. The ground being the pin that is different to the other three. Hope that makes sense.

rusty ol ranger · Jul 22, 2009

Huh?

I was talking about the store bought 10 dollar adaptor to go from a 7pin to a 4flat....

looks like this...

Well, basically, but mine is all one piece.

There is no "Y" adaptor that plugs into the harness, the trailer lights are wired directly into the truck lighting system.

But i dont have the stock taillight connecter hooked up. Im wonderin if that might be whats causing the goofy problem? Its not hooked up because theres nothing to hook it to, the factory box is in the scrapyard. The magnetic towing lights was just a temp solution till i got the time to wire up actual lights.

later,
Dustin

BRUTUS_T_HOG · Jul 24, 2009

it could cause the problem because the trailer lights are most likely wired into the harness that is not plugged in... but as i said before.. try to provide a ground at the white wire of the trailer harness and see what happens

rusty ol ranger · Aug 2, 2009

Shit.

There was no white wire on the stock harness.

A green, red, yellow/black and black.

Well like an idiot i grounded the yellow/black wire to the frame, switched on my signal, and it worked in the truck for like two flashes and quit.

It blew the fuse, replaced the fuse, and flasher can (the little thing that makes the tick tick tick noise), but now i have nothing, no front signals, no back signals, nothing on the dash, not even a "tick tick tick" noise.

I know the Turn signal cam has always been screwey (it never wanted to recenter right after turning) would this cause the problem...or could it be the switch?

Also...autozone wanted 120 bucks for a new switch for a 78....advanced lists them for 50 bucks from for a 77....and nothing for 78/79. The 77 Should be the same shouldnt it?

later,
Dustin

orfordguy@yahoo.com · Sep 30, 2009

taillights

I own 4 of those fords in differant versions the part no one thought of is that the taillights have a ground in behind the taillight, remove the bed remopve the ground and light function... runn a wire from the harness to hte frame and screw it down... that should fix it.. or pull the harness from the bed if you have it and install the wiring into another set of lights, i prefr the truck stop leds..
:icon_cheers:

rusty ol ranger · Sep 30, 2009

Thats what i was trying to do.

But i grounded the wrong circuit, now i dont have turn signals in the front or back.

I did have them in the front. But not in the back, now i have none.

I have hazards though.

later,
Dustin

1badexplorer · Sep 30, 2009

If your turn signals don't work but the flashers do, it sounds like you burned up the flasher canister. There should be two round canisters plugged into the wiring up by your e-brake peddle and column. Locate the one that runs the turn signals. This can be done by turning on the flashers and unhooking then one at a time try taking the good one from the flashers and swapping it with the turn signals and see if the problem is the same or opposite. IF its the same then you know that both canisters are good. If opposite, then that is your turn signal problem.

rusty ol ranger · Sep 30, 2009

I had them working for a while eariler (in the front) after i poked around at the fuse panel with a test light.

Then they quit again.

later,
Dustin

orfordguy@yahoo.com · Oct 26, 2009

lights

replace the fuse and the flasher, make sure the gruond is the correct one and try again if that doesnt work you may have burned up part of the blinker switch testing the column plug with it on will tell you iof theres power in and out. good luck

78 F350 Electic issue....

rusty ol ranger

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