truck is a 1990 F250 460 7.5L 4x4 standard cab

when I purchased this truck it had no tail lights or brake lights, and the e4od transmission was dead.

I just completed swapping in a 1997 E4od with only 60k miles.

Just need to get my tail lights and brake lights working.

headlights work, brights work, turn signals work, reverse lights work, if I turn the dimmer all the way to the left the BED light above the rear window works.

tail lights never come on... very rarely I can get the brake lights to work, seems like they work most often if I put it in reverse, (which triggers the backup lamps too) That leads me to think it *might* be a ground someplace....

The interior illumination lights like the dash and ac controls do not light up when the headlights are on, I have tried to adjust the dimmer but they just never come on.

checked all the fuses in the cab, they are all good.

main issue Ide like to resolve is the running tail lights and the brake lights. Is there a specific place I could be looking for a bad ground or switch or something?

Thanks so much for any and all help.

 

Dumb question, but you have checked the fuses right?
And best I can remember the only ground on the rear of the truck is in both taillight buckets. There isn't another ground in the harness till the cab. Maybe the socket itself is dirty or wore out. But sounds to me like a ground too. Should be a screw grounding the harness to the bed behind both of the tail lights. Pull the tail lights and start there. Hope this helps

 

Oh yeah, I checked the fuses, will pull the tail lights and take a look, thanks!

 

I pulled both tail lights, there is two plugs per tail light... I don't see a ground anywhere.... what do you mean in the buckets... do I need to seperate the lense from the tail light housing... or is the ground someplace else on a 1990?

 

Seems likely that the brake lights and tail lights are separate issues. This is cause the turn signals work and they share the same bulb, wire, etc. with the brake lights from the turn signal switch back. So if the turn signals work then all the wiring in the back for the bright side of the bulb is good. So the brake light issue must be "before" or in the turn signal switch, I would start at the brake light switch.

Tail lights could be lots of things, well except a ground, if the reverse and turn signals work, then the ground is good, they share a common ground. Do the front running lights work? If so the switch should be good. Could be as simple as both bulbs are blown, but more likely the connection at the back of the bed is f'd up from years of morons fixing trailer lights

Edit after seeing last post - IIRC there are 2 grounds at play here but the primary is at the back of the frame near where the frame harness connects to the bed harness under the drivers side of the tailgate. There is also a ground in front of the tank selector valve, but I'm not 100% the 2 are connected. But as I said your problem is not a ground.

 

By bucket I meant the hole the tail lights fit Into. Follow the harness to past where the wires for both sockets meet at the main harness. Somewhere around there, there should be a ground wire that comes out of the harness and screws to the metal area behind the tail light with a small metal screw. It should be like that on both sides

 

I really don't want to get into an argument cause really I don't remember and it's not his problem, but that doesn't sound right to me. I'm pretty sure they are grounded on the frame, that the bed has no grounds as it would be a bad idea anyway, as the bed itself isn't grounded very well and Ford didn't rely on bed grounds as so often the bed came off. All the wiring including grounds is on the frame until the very last moment and at a plug for easy removal.

I should remember this better, I just did a bed swap on my 89, lol

Edit, come to think of it I just pulled the taillight harness out of the back of my old 89 bed and don't remember removing any ground screws.

 

On the front of my truck I have the head lights and the turn signals.

When I turn on the headlights the headlights work... is the running lights in the same fixture as the turn signal? if so they didnt come on (dont see any other place for a running lights)

edit: I think you might be on to something with idiots fixing trailer brakes, gonna climb under the back and see what i can find.

 

theres a rats nest of electric tape and butt connectors gonna start checking all these connections out.

EDIT: the tape and butt connectors are on wires that are going to two plugs that look to be specifically for trailer hookups, the main harness does not have any splices.

I am going to unplug the two plugs that goto the bumper trailer hookups, maybe there is a short

 

By running lights I mean the amber lights on the corner where the turn signals are. When the headlight switch is in the first notch you should have dash, tail light, and front running lights all on but no headlights. The front corner lights have two elements a bright and a dim just like the rear. A bright for the turn signals and dim for the running lights.

Sounds like no dash lights, no tail lights, and no running lights. These items are all the first notch of the headlight switch and might likely all be related by the same problem in the switch. The dome light and bed light should all turn on with the dimmer turned all the way, but this is not related to the dimmer function and dash lights.

 

ok so the running lights and dash lights is probably the switch being bad. I will get a new switch.

for the brake lights, I noticed something else. with how they intermittently work. for one its just the drivers side that works. (when it works) and I tried swappin bulbs with the passenger side, still only drivers side works, so its not the bulb

the other thing I noticed... when my brake lights decide they want to work, I can step on the pedal over and over and they work, then if I turn on the blinker to either side... the brake lights will no longer work. if I wait like a minute then the brake light will work again... until I use the blinker, then brake light wont work....

so since only drivers side brake light works some of the time... im guessing theres a trouble wire to the passenger side.

In addition maybe something with the blinkers is shorting out the brake lights?

I have no idea, harness looks good back there.

 

In that case the brake light issue is certainly in the dash/column. Likely the turn signal switch. As the brake and turn both use they same light they both go through the turn signal switch. Between the switch and the bulb the brake/turn share everything. When the turn signal switch is off the brake lights go through to both rear lights. When you switch to turn left for example it disconnects the brake light and turns on the turn signal.

So sounds like you likely have a worn out turn signal switch.

 

COOL! so this is for my white 460 F250, I recently purchased a red 7.3 diesel F250.

I just took the headlight switch from 7.3 and now my running lights and tail lights are working, as well as the dash lights. (7.3 will get a brand new one once I get to working on it again)

So that part was indeed the switch....

now for the turn signal switch... I gotta figure out how this steering column comes apart to replace it.

 

so I pulled the horn/cruise plastic on the front of the steering wheel, and then I pulled the 15/16" nut in the middle, I am ripping on this steering wheel with all my strength, it dont wanna come off.

(got my wheels straight and steering wheel in straight position, so its easy to reinstall)

 

Yeah you'll need a puller, it screws into the steering wheel and pushes on the column. Chances are you can barrow one from a local parts store. Or they are pretty cheap at places like harbor freight.

It's indexed so you don't have to worry about installing it straight again.