I REALLY need help!

Hello folks, Im in a situation here. Im just a back yard mechanic and can do basic repairs, but this one just has me stumped.

I just recently purchased a 1998 GMC 1500 2 wheel drive from my best friend about 3 or 4 months ago. He purchased it brand new in 98 and of course is the original owner. I got a hell of a steal on it and basically told him I still want him to do all the maintenance and repairs on it, only I will pay for it of course. My biggest issue right now, is the past few weeks I keep blowing the turn signal fuse. It all started randomly, I thought it might have been just one of those things where the fuse had just about enough and popped. But I was wrong. I replaced the fuse, and not 2 miles down the road it blew again the second I hit the switch. It seems to only happen when I hit the right turn signal. The only other thing I have on this circuit is my LED tailgate strip that blinks along with the signals, but I even went as far as unplugging that from the trailer harness and still had the same problem. Just for kicks I pulled the right rear tail light out and pulled the bulbs to see if there was any corrosion. I noticed the turn signal bulb was a little smokey on the inside, so I replaced it thinking that might have been the problem, but of course it wasn’t. I pulled the front turn signal and did the same, but all of the bulbs were fine, and was no corrosion to speak of. Wiggled the bulbs around and drove around for about a week and a half with no problem until tonight. It popped the fuse again.

I really dont know what else to say. I did notice that when the fuse is blown, I can take the truck out of park without stepping on the brake pedal, and when I put a new fuse it, it goes back to normal where I need to depress the pedal to get it out of park.

Does anyone have any idea on where else I should start? Like I said before im just a back yard mechanic and know a little bit, if someone can give me some instructions on what I should look at, I can do it. I would greatly appreciate it. Thanks in advance!

You likely have a chafed wire somewhere in that circuit that’s shorting to ground intermittantly. It sounds like that circuit must be feeding off the same buss as the switch in your brake pedal lever that activates the tranny lockout, and weird secondary effects can happen with grounded wires.

Often the best fix for wiring harness problems is to string a new wire.

This is probably a good way to blow a good friendship. I would only sell a vehicle to a friend if he allowed me to tell him all the things that were wrong with it and what would probably go wrong in the next 2 yeras. And I would not offer to fix it.

I had a similar situation with my trailer, I thought the thing was haunted, All looked good and tested good but 5 miles down the road it was fried, i checked all connections and only solved the problem by replacing the whole taillight assembly.

I’m going with the chafed wire / short somewhere…I dont know what a wiring harness will set you back, but it may be grounding somewhere (also what may be defeating the brake / shift release issue as well) and you may spend 3 months looking for it…and not find it…

You stated you already removed the trailer harness and that was a very good thing to do as a lot of these kind of problems come from there.

Since the fuse blows when the turn signal is ON then naturally the problem is after the switch. I would first look for the trouble near the rear light and also check the area between the bed and the cab. Check the front wiring also near the lights. The problem could also be in the steering column and you could try disconnecting the wiring to the right side signal and then see if the fuse still blows out.

The right turn wire, between the turn/hazard switch and the turn lamps is shorted to ground, which blows the turn/hazard switch fuse… The power wire, from the ignition switch to the turn/hazard fuse is shorted to the brake light wire after the brake light switch. The brake light circuit powers the shift lever release.

Two wheel drive WHAT? Suburban? Pick up? K1500? C1500? Don’t know?

Just out of SHEER curiousity… you said that you drove it around for a week and a half and everything was fine until “tonight”? Did you wash the truck, did it rain, or did you drive through a puddle? just a thought.

You did say you disconnected the LED light strip, but did you look at how it was connected? Did you look at all the wiring for the trailer harness? I would definitely check all the grounds on the frame or the like.

I would pull the taillight sockets out and check them over. Focus more on the right taillight.

If you need to, Haynes, Chiltons, and even Mitchell on demand are great books with great and helpful wiring diagrams. It’s sure helped me in a pinch.

Blow on them before you roll them.
(Good Luck)

This is a two wheel drive extended cab short bed pickup. Sorry I thought 1500 would have been enough but I wasnt thinking of the suburbans and what not.

I did wash the truck a few days ago but you would think I would have had a problem with it directly after driving away. It was raining yesterday when it happened but it has also happened during warm sunny weather. So I really dont think that is the problem. Good thinking though. I thought of it myself.

The LED tailgate strip was connected securely to the trailer wiring harness with electrical tape wrapped around it a couple of times. Not excessively but it was wrapped around to keep wet weather out. This weekend my friend and I plan on crawling under the truck and going over the whole harness and check all the grounds. Until then, I guess I will drive with no turn signals. People hate it, but oh well. I only drive a mile down the road to work so they can honk and give the the finger all they want until then. Its only a couple of days…as bad as it sounds.

I did get on Mitchell On Demand online and looked at a diagram on there to see exactly what was on this circuit. That is how I found out for sure that the park release switch was on the circuit. Unfortunately it did not tell me where the grounds were for all the circuits. So that really didn’t help me much.