IG1 Fuse Keeps Blowing

Alright, fellas! Update:
I did as Jimmyh suggested. I backed up to the trailer, set the E brake, slipped the tranny into Neutral and THEN hooked up the trailer. NO BLOWN FUSE. I then ran through all the lights to make sure everything was functional and it was. As soon as I went and put the shifter back in park-Fuse Pops!
Park/Neutral switch? I’m not familiar with this one. Not an issue I’ve ever encountered on a vehicle.

 

Can't be the park/neutral switch or it would blow the fuse with no trailer connected.
It has to be something on the trailer shorting the reverse circuit, it can't be anything but a mis-wired plug or short in the trailer wiring.

 

The Park Neutral Safety Switch is on the passenger side of the transmission.



The Circuit goes like this:

10 Amp IG1 Fuse >> IH1 Plug >> Park neutral Reverse Switch >> ID2 Plug >> BE1 Plug >> T12 Trailer Socket.

 

I agree with Dm93. Everything points to a trailer wiring issue.The puzzling part is that it doesn't blow fuses with the other two vehicles...

The test above was to clarify that the reverse lamp circuit is more likely where the problem lies.

I would disconnect the reverse (backup) wire on the trailer side if possible and test it again.

 

Ill ask again did we look at the truck side of the equation? Not just a visual inspection, but actually take the plastic housing apart and inspect inside. Could be something loose in there that gets shifts when a trailer is plugged in?

 

SR-71, to answer your question-Yes. To the best of my ability, I pulled harnesses of the truck apart, pulled wires out of their wire looms to chase it looking for loose or shorted wires. I found nothing wrong.
What DM93 makes sense-but only to a certain degree, No problems with the other vehicles. with that said…I will disconnect the reverse wire from the trailer plug next and see if that does anything different. I really want to thank you all for your input! I’ll keep you updated as I continue digging.

 

Your trailer reverse fuse may be blown on the other 2 vehicles and you may never know it as most modern vehicles fuse trailer lighting separately from vehicle lighting and most trailers don't have reverse lights.
I bet if you check the trailer backup light fuse on your other 2 vehicles you will find it's blown.


2020 4Runner



2019 Ram 3500