First off, this forum is phenomenal! A special thanks to disco mike for helping me in the past...

Now onto my issue, albeit minor. I installed a factory trailer wiring harness in 2004 along with the rectangular adapter when I bought my truck and haven't used it since then. At the time it worked well. I've had it on for the last 8 yrs just sitting there. I used it maybe 3 or 4 times , but haven't used it for at least 3 yrs.

I plugged into a boat trailer yesterday, and nothing worked (no brake lights or turn signals.)

Is this a common problem? After I check the connection in the rear brake light, How would I go about troubleshooting it?

Thanks in advance.

 

Here's pix of the harness to adapter connector, may have slipped loose. Also two pages of wiring diagrams, there are several fuses under hood that could be involved.

 

Thanks Savannah. I determined that it may just have been corrosion, I did a little sanding and cleaning, and I am now getting power, but that didn't fix the problem.

I tested it with a multimeter, and I'm getting about 10.75 volts coming through both the 7 pin and the 4 pin after the converter, but the trailer brake lights and turn signals still aren't coming on.

They did work with another truck a week or so ago, so I don't think it's the trailer.

How much power should be coming through the trailer wiring?

 

13 volts and some change. You'll want to also check the ground, which is black wire, goes to connector C0808, in attached pix.

 

The ground looks good.

I tested it on a uhaul trailer and it worked with that one. It's still putting out only about 10.75 volts and won't light up the boat trailer, though.

Could it be the 8 yr old harness that's keeping the voltage down, or is there something else that I can check?