Brake and Turn Signal electrical gremlin (1 Viewer)

[87warrior]

My 99 has developed a fun electrical gremlin. When I apply the brakes or use the left turn signal, the instrument panel lighting illuminates. Since the behavior is difficult to explain, I have attached a video of what is going on:



I have experience with poor grounding on trailers and corroded lamp sockets on Jeeps that have produced similar behavior, but I've never had that cause issues inside the cabin.

Here are a few things I have done that may weigh in on the root of the problem:
- I converted the dash lights to LED 3 years ago
- I installed a plug and play Curt trailer wiring kit last year
- It finally started to rain in Kansas and I first noticed the odd behavior when driving through rain
- My sunroof has leaked and is currently sealed up with Gorilla tape

I need some guidance to start troubleshooting this.

 

[Trunk Monkey]

Check your sunroof drains and check your windshield seal all the way around for leaks.

 

[Leandro]

I had a similar problem.
It was the electrical connection for the trailer hitch. Removed it and voilá. No more issues.

 

[mrahc]

I swear to God I just came here to type this EXACT issue I'm having in my 98 that started today. It must be the moon cycle. I'll do what @Leandro said right now. Where is that connection by the way lol...

 

[mrahc]

Oh also, my ABS light came on out of nowhere this morning. Not sure if that's also an affect of this.

 

[Leandro]

Where is that connection by the way lol...

Mine is in the trash LOL

Mine was an aftermarket, can't remember the brand. Basically followed the cables until I found the little box. It was behind the rear bumper, passenger side.

 

[ScubaJon]

I had a bad ground on my trailer and it caused this problem. I assume if nothing is plugged in then you have a bad ground in the trailer wires under the truck.

 

[mrahc]

So. I found my issue. Trailer wiring harness had a bad ground... And almost caught fire. I'm very lucky to have gotten home in time to get this. I can't seem to get the connector unplugged can someone give me a tip on that... Thanks.

 

[87warrior]

I unplugged the trailer harness converter this evening. Everything went back to normal! I'll investigate the ground, but I am worried the converter is bad.

Is there a reliable trailer harness converter available for the 100?

 

[Leandro]

I'm glad you guys found the issue, that drove me crazy for a couple of weeks until I found it
Also, I blown the brake light fuse twice so had to manually unlock the gear selector.

I've been helped so many times by this forum that is nice to contribute back.

 

[mrahc]

Edit: figured it out

 

[mrahc]

That was the connector. Still smells burnt.