Frustrating short

[bosco200]

Ok guys heres the problem, I keep blowing the fuse that runs my sidewarker, front blinkers, tail lights, and gauge lights...ill move wire around and look for broken wires, but cant seem to find any, then ill put a new fuse in after moving wires, and the fuse wont blow, but once i hit that wrong bump in the road, boom, the fuse blows....can anybody give me an idea of where this short would be?????

[WAAF]

sorry it could be at any inch of the harness that feeds those lights..

[cdowns]

i'd start by getting under the truck at the rear bumper // scewed up remnents of aborted trailer connection hookups// then work your way slowly foward ecpecially where the light harness is held in place on the frame rrails by the metal clips

[Longhorn Man]

was your truck just painted? Looking at the avatar, it looks to have nice paint. If the bed has been removed, look for pinched wires from the bed installation.
Otherwise, I agree with the under the bumper trailer harness hack jobs.
Another thought, the dome light is on the same fuse... does it work? Follow the orange and white wires under the door sill plate on the drivers side and look for where it is shorting to ground.
Remember, your brake lights don't work when that fuse pops.

[bosco200]

Yeah I painted my truck about 2 years ago, ive looked at the wires that run along the frame, and I put electrical tape on the spots where the clips were (thinking that the clips may have rubbed through the wire) but i will check back by the bumper too, and no my dome light doesnt work either.

[bosco200]

Ok so I went outside and looked at the wires under the dash down by the fuses, the ones that run to my ignition, my lights, my wiper, blah blah blah, all that stuff, and after that i popped in a new fuse and they all my lights worked again, so I take off driving and barley hit a slight bump in the drive way and boom theyre all gone, so I looked at the wires again, they all looked good, so I took my fuse box off and looked at all those wires, and they are all perfect, I even checked the ones that were plugged into the fuse that was gettting blown and they were perfect, so I put electrical tape on the wires closer to the fuse box....I put it all back together, pop a new fuse in, and its good...I back up my truck and begin going up my drive way, and there goes the fuse again......So im guessing it has to be under the hood, or under the bed, not in the cab?

[oldgold70c10]

I had a very similar problem a few weeks ago with the same circuit. Turned out to be the fuse holder had some corrosion & would loose good contact with every bump & cause the fuse to heat up and pop. Noticed in dim light the bad contact would actually glow when pressing the brakes.

Cleaned the contact with some emery cloth & no glowing fuse contacts and no problems since.

[72lb4x4]

There's a plug at the FW by the throttle cable that has for the cable leading to the rear of the truck. Disconnect it and see if the fuse blows.

If not, its from that connector back...

[VetteVet]

I have been studying the wiring diagram on the lights and I agree with Longhorn Man. The orange wire from the fuse panel goes to the brake light switch, the head light switch, where it feeds the parking lights and the dash lights and also the dome light. If the orange wire to the dome light touches the cab ground then it will blow the stop tail park light fuse and the gauge lights won't work either. Besides the sill plate under the drivers door I would check the dome light itself.

[john_p]

look at any area where the wire has been opened.. trailer lights always come to mind.. if the bed was off, i would check that area.. your right that is a tough one to find

[bosco200]

Ok guys, well I thought I had it fixed but I guess not, I taped the wires that run along the frame thinking it might of had a break in the wire, and the fuse didnt blow for about 3 days, but yesterday I was just sitting at idle and it blew, so today, I took out the break light assemblies and looked at the wires, the yellow wire had about 3 spots with bare wire, one spot was sitting on the metal, so I think well there's my problem, so I get new wire in the assemblies, then I go to test them and, now I have no blinkers when the lights are pulled, when I do try the blinkers with the lights pulled, they blink very very slow in the cab (on the Bezel) the right blinker (in cab) blinks way slower than the left, and the arrows are lit up, but not really bright, (they've been like that for a while).....so now what?

[bmfm64]

Fix your grounds. I had the same problem, took apart the taillights that worked fine and reassembled to have the symptoms you are describing. I ran a dedicated ground from the ground on the box behind the taillight to the frame on both sides and that fixed my problem.

[Longhorn Man]

now you have a ground issue most likely. Remove the tail light buckets again and clean up where the bolt goes through and into the bed.

[bosco200]

Alright Ill go and give it try and ill let you know what happens.

[bosco200]

Ok I cleaned them again, and they still didnt work right, so I found a ground wire nearthe bumper, so I cleaned a spot on the bed and the frame to get bare metal, and moved the ground wire, they blink with the lights pulled, but they still blink VERY slowly, the right take about 6 seconds to blink, and the left take about 3......also, are my front side markers suppose to be on when I pull the lights?

[fixit-p]

The only way to tell the actual condition of the ground is to test for voltage drop on the ground side of the load. If you have a multimeter test the light housing and light buckets for power with the negative probe of the multimeter connected to battery neg post. Any reading above .2 volts indicates a poor ground condition see image below.

[bosco200]

Ok guys, I added some grounds, cleaned all my ground wires really well, cleaned the housing for the brake lights, and now, my blinkers work when the lights aren't pulled, but they still wont blink when the lights are pulled, I have no brake lights, but the brake lights come on when the lights are pulled, i just have no brake lights.

[fixit-p]

..

Originally Posted by bosco200

Ok guys, I added some grounds, cleaned all my ground wires really well, cleaned the housing for the brake lights, and now, my blinkers work when the lights aren't pulled, but they still wont blink when the lights are pulled,Sounds like you still have a ground issue. If you can, try the test I outlined in my previous post.

I have no brake lights,
The brake lights go through the turn signal switch, check for power at the brake light switch and we can troubleshoot from there
but the brake lights come on when the lights are pulled, i just have no brake lights.

[bosco200]

Ok Ill do the test tomarrow thanks.

[bosco200]

I still havent got to doing the test yet, but when the lights are pulled, and i put the left or rights blinker on (they both do they same) I can see them blinking, but the light its self doesnt delay to where u can see that my blinkers on, but if u watch very closley u can see it blinking in there...my front right side marker is either dim or just doesnt come on at all, the only light that will flash when my lights are pulled is my front left side marker, My front marker will flash when lights are pulled, and it flashes on the gauges, but the right one wont flash on the gauges, my alternator is getting 14 volts, so are my front and back lights when the lights are pulled.......getting very frustrated.

[bmfm64]

Originally Posted by bosco200

I still havent got to doing the test yet, but when the lights are pulled, and i put the left or rights blinker on (they both do they same) I can see them blinking, but the light its self doesnt delay to where u can see that my blinkers on, but if u watch very closley u can see it blinking in there...my front right side marker is either dim or just doesnt come on at all, the only light that will flash when my lights are pulled is my front left side marker, My front marker will flash when lights are pulled, and it flashes on the gauges, but the right one wont flash on the gauges, my alternator is getting 14 volts, so are my front and back lights when the lights are pulled.......getting very frustrated.

I don't mean to be rude but if you're not gonna do the tests and try the things we keep telling you to do why would we keep helping? Do the tests that have been outlined and try the grounds again and let know.

[bosco200]

Ok I did the test and got .1, so the ground is good, I took out the front marker and cleaned the crap out of them, put them back on and there was no change, but then all of sudden my left front marker was dimmer than the right....I also noticed, if my radio is on a static channel, and I pull my lights the static gets quieter??? O also now the right signal indicator wont flash in the gauges.

[fixit-p]

Did you do the test on all affected lights and also the shell of the bulbs as well (poor ground could also be between bulb and socket).

Sometimes understanding why ground faults act oddly can help in troubleshooting so here is a simple description of a bad ground at the left brake/taillight.

Anytime turning on a seemingly separate load changes the state of a seemingly unrelated circuit it points to a bad ground. That's because some of the circuits share a ground like the Stop/Turn bulbs have a dual filament, if one bulb looses its ground then current will flow from 1 filament through the other seeking an alternate ground path. Now lets say if the left brake light was not grounded properly and found an alternate ground at the licences plate light, the left brake light will illuminate until the taillights are turned on and the alternate ground path is gone because the taillight circuit is hot and the left brake light would have power on both sides of the filament (no ground) turn off the taillights and the alternate ground path is restored. The pic below illustrates this the ground symbols which are circled are broken and the only remaining ground is at the lic lamp.

The pic below is a byproduct of a CAD drawing which was provided to me by board member Edmond so credit goes to Edmond for producing, sharing and allowing me to use it to help other board members.

[bosco200]

WellI fixed it, the wires to the front markers were switched, as well as the back lights, and the reason my battery was getting drained was my brake light switch was out of adjustment, the reason my right blinker wouldn't blink in the front is that the prong in the adaptor was loose and it wasn't touching the other prong, thanks guys.
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[fixit-p]

Cool, I'm glad you were able to sort it out. One thing that kills troubleshooting logic is when the circuits have been changed (dam P.O.'s).