Trailer wiring issue, possible TIPM

[stickboy]

I'm pretty confident my issue it the TIPM, but I wanted to get some extra opinions before I lay out the money for a replacement.

My left brake/turn light for my trailer wiring is not working. I have checked it with a wiring tester and also at all the connectors from the bumper to the TIPM (18YL). I'm seeing the following:

Truck off = no voltage
Brake on = 10.5V
Turn signal/4 ways = 10.5V steady
Truck on, or a few minutes after light were on = 10.5V

The left turn signal works for the regular truck wiring. The right trailer brake/turn light works and I see 12V on it when the light should be on and either 10.5V or no voltage when it should be off.

I also have an intermittent issue where the trailer marker lights will turn of and won't run on again until the trailer connector is reset. This has been happening since I got the truck last winter.

I am going to install a Draw-Tite 119192 this winter to protect the TIPM before I start towing my camper again in the spring.

Am I correct in thinking that my TIPM needs replaced, or is there something I'm missing?

If I do need a new TIPM, I am planning on a Dorman rebuilt one. Is there any place that is better to get it than the regular part stores?

Thanks for any help you can provide.

 

[Motorhead]

Reading voltages with just a meter with no load on it can fool you thinking a circuit is good. You might want to look at the TIPM circuit board first to see if there is a place burned or a loose solder joint. A burned circuit can also be repaired with a wire jumper. A NEW or REBUILT tipm will also be at risk if the issue that killed the original tipm isn't fixed.

 

[stickboy]

Thanks Motorhead. It didn't occur to me that I could open the box up and do a visual check for an obvious issue. I've done some work on simple electronics, but assumed the TIPM would be too complex for me.

I had enough moisture in my C135 connector to cause shorting, but that has been solved since I greased it up. The wiring near the bumper was hacked on a little by the PO and still needs cleaned up. I also found an oversized fuse in the TIPM. I don't see any other obvious damage in the harnesses, so I'm hoping I've caught whatever caused this. I will be isolating the trailer lighting to protect the TIPM further and replacing the hacked up wiring with a repair kit before hooking up the camper in the spring...