Dumb Trailer ABS issue

15 Volvo vnl 670

2 trailers were doing the blinky ABS light crap while braking. 40 fuse kept blowing.

I bypassed the blue aux wire directly from the back of the fuse box under the hood to a jumper harness that connected the rest of the stock 7 pin wiring except for the blue aux wire (with the new one from the fuse box) into a new receptacle. Worked for ten mins and blew a fuse. I then cut that new wire and rigged up a fuse holder directly to the battery with a 50 amp capable toggle switch. That worked for tens mins and the fuse blew.

I've replaced the pigtail right when it started happening.

Whenever it fails I'm getting the trailer abs light on the dash still when I hit the brakes.



Two trailers
Two different power sources
New pigtail
Part of old pigtail was cannibalized to make AUX wire adapter harness BUT the fuse still failed when that wasn't connected.
The push in receptacle on the back of the cab tested good btw. But it's intermittent so idk.


What am I missing?!

 

Double post

 

I'll try that. Thanks!
I also think I'm going to test all the lights with the pigtail disconnected to check for shorts in the factory harness.

 

Looks like it's probably in the trailer harness to the abs module. I disconnected it and drove 7-8 mins to my drop and it blew the fuse for the abs that's hooked straight to battery and bypassing the factory truck wiring.

Figures I'd get two trucks that have ABS issues in a row. I'm still going to bobtail around a little later to see if for some dumb reason the pigtail I just bought is bad but I doubt it is.

 

It ended up being a chaffed wire behind the pigtail receptacle of the trailer btw. Now I have an adapter to test factory wiring I guess lol