Chrisreyn

OK, today i installed a brake controller and hooked up to the trailer to test it. It worked fine, but when I pulled out on the headlight switch , I have no lights.
Get out the test light and start trouble shooting and have no power at any pin in the 6pin connector except brakes.
Pull the trailer plug out and start checking wiring, only one working is left turn signal, and I accidentally touch the edge of the plug with the test light, and I hear the arc and all the lights on the truck go out.
I believe I have blown a fuse, so go get a new one, but the fuse wasn't blown. Checked it with the test light, fuse is good, have headlights, brake and turn signals and dash lights, but no tail lights or marker lights.
Double and triple check the fuse, check the fusible links under the hood, and still no sidelights. Headlight switch is new( 3 days old) and dash lights, headlights and dash-dimmer is working.
Checked everything I can think of and cant isolate why the truck side lights/tail lights aren't working. I think ther eis a circuit breaker in teh sytem per the 91 wiring diagram, but I cant find it, adn how do you reset them anywyas?
Any ideas guys.. I am pulling my hair out on this..
Oh, I completely disconnected the trailer plug until I correct this............

HELP!!!!!!

dcwm

You didn't say whether the front running lights are working or not. If they are burning then I would look for a bad splice somewhere along the frame behind the cab. If the fronts are out too then suspect a bad connector or the new switch. Trace the running light wires back until you find voltage.

Does the running lights have a dedicated fuse/circuit?

Chrisreyn

The ONLY lights are teh headlights, dash lights and turn signals. The front, side and rear markers are all kapoot.. no running lights at all..

wannadiesel

Which fuse did you check? #4 is all the undimmed lighting, should be a 20A. They are labeled in a confusing way, so make sure you are checking the right one. There is a fusible link before it, it's gray.

swampthang

if you figure it out let me know your old truck is the same way right now all lights working no park lights or tail/run lights the break and turn work as well as the head and dash ?? i found this out the hard way got pulled over !!! grrr lol


jason

wannadiesel

Swampthang, if the fuse and fusible link are good then throw a headlight switch at it. The running light wiring is the same on the older trucks.

Chrisreyn

Jason, told ya it needed a headlight switch! wiggle the handle and they come on, but teh dash lights sholdlnt be working if it is the same issue.. so I am not sure....sorry, hope ya got a warning!


Dave, I checked ALL of the fuses and they are all good. Is the fuseable link you mentioned under the dash or the hood? Checked all the ones under the hood and have power to the line behind the link, so they are OK.
I see in the wiring diagram the headlight switch has a circuit breaker in it, does this flip and then reset? or is is a misnomer? Hmmmm, wonder if the new headlight switch could have "blown" somehow..

wannadiesel

The breaker is only inline with the headlights themselves, it is self resetting. When it cools off, the contacts close.

The fusible link is under the hood. It should be gray. I really think it's that fusible link unless you fried the new headlight switch.

At the headlight switch, check for power on the pink wire with the red stripe. That's the feed from fuse #4. The wire out to the lights is black with a yellow stripe.

Chrisreyn

Ok, thanks Dave, I've knocked off for the night but will check those in teh morning.

Gieco wasnt too far from wrong... yer one of the ones we count on for knowing stuff the rest dont...THANKS

wannadiesel

I think I'm gonna take it out, I think it looks too cocky.

Chrisreyn

Naw, leave it... looks OK and it advertises Gieco being humble?

swampthang

oh ok i dont remember tha tone but oh well that is what i just went and bought lol ya io got a warning you got to love working for the fire dept ya know all the cops lol ad removed

Jason

BearKiller

This is just a wild guess; but, if you tapped the trailer tail-lights into the truck lights, using one of those crappy squeeze-together scotch-locks, or whatever they are called, then you could have cut the wire in two inside the splice, thus killing your parking lights.

Trailer lights should always be independent of the truck light wiring, and have a switch of their own.

EClancy

I was having similar lighting issues, and when i replaced my ground-to-body and ground-to-frame/engine cables, the lights worked great. Just an idea to look at

Chrisreyn

OK, instead of blowing the fuse, it smoked the headlight switch I put in last week!, Luckily it has a year warranty and they exchanged it out. Lights are all good now.

Next is to try finishing getting the trailer lights hooked up again, and BearKiller, agree aboput "scoth-lock" connectors, never seen one that didnt corrode thru.
I get bullet connectors( watertight) and use those, two sires on one side, one coming out the other. Increases resistance in teh circuit by a hair, but much better conduction ability and less exposure to corrosion.