Blowing fuses

[dirtautoguy]

Hey, I think iv got a bit of a unique problem here and thought I would throw it out and see if anyone had any ideas.

I have a 1996 k1500 regular cab short bed pickup iv had for about 8 years (it was my first truck and got me into wrenching on things) anyway iv used it to tow various things and camping over the years and never had a issue with the trailer lights. OTHER than once in a while the right turn signal would act up on trailers sometimes.

We recently got a 21ft camp trailer that we took on it’s maiden voyage this weekend I took it up a day early and on my way back home I found that none of my turn signals work, the camper is a 1988 and figured the lights just needed some attention. I replaced the fuse and all was good

The next day We headed up to camp with our flat bed trailer on and it blew the same fuse. Twice. Fast forward to
Our trip home same flatbed trailer was good all the way home untill I unhooked the trailer soon as I did the fuse blew again. Of course by this time iv bought a million of those Dang things. We went back and got the camper and all was good I was paranoid and kept checking my signals and. The exact same thing all was good untill I unhooked the trailer! It blew immediately after that.

So it seems as though something to do with the trailer unhooking from the truck is grounding something out????

Up untill now I haven’t had any issues with the lights. Leading up to this weekend I have wired in a brake controller which seems to work great.

I replaced the trailer plug receptacle on the truck when I did the brake controller because the old one looked as old as the truck.

I replaced the 4 pin trailer pigtail plug from the connectors behind the bumper to the trailer plug receptacle because the white ground wire had been cut off ( not by me) and was grounded directly to the frame, and the green right turn wire was corroded really bad where it went until the 4 way plug.

While at camp I pulled the plug receptacle back out and made sure all the wires were good and not touching and did a quick inspection in the area and didn’t see anything obvious.

I have a multi meter and a test light I’m just not sure where to start. As long as there is no trailer it doesn’t blow a fuse. And with a trailer most of the time it’s fine untill you unhook the trailer for some reason. All turn signals, brake lights, hazards, running lights all work the way they should untill fuse 16 blows and I lose turn signals.

Any ideas?

 

[dirtautoguy]

Just did a little more investigating and found that my multimeter says I have continuity between the ground pin and both left and right turn pins..... I’m pretty sure I shouldn’t have continuity there should I?

 

[gric_az]

If the fuse is blowing, even with 2 different trailers. The problem is obviously on vehicle end. Check wiring again. What I find odd is that it only does it when disconnecting? Something is loose and making contact. Maybe from the wiggling motion of removing plug?

 

[dirtautoguy]

That’s what I thought too. I tried to simulate that by wiggling all the wires on both ends of the the harnesses but nothing has happened. I think what I’m going to do is put a bigger ground wire and connect it directly to the frame like the truck was when I got it and try that. Plus I do not see in any diagrams where the t connectors have a place for a ground.

The trailer should ground somewhat through the hitch but I noticed my ball has quite a bit of nasty rusty stuff plus the mount is relatively new and is not bare metal so it probably would not be a good ground.

I’m going to try to do this tomorrow afternoon