Posted 2011-12-29 4:38 PM (#139719) Subject: Brake fuses blowing like a dead short....
Member
Posts: 9
Location: Missouri
This setup has been on this truck for YEARS now.... but very recently, the fuses started blowing, then, they blew right off, like a dead short. However, if I CUT the red trigger wire, from my brake pedal TO the box.... the trucks lights work fine, NO fuse issues.Further... the Trailer Brake Box fuse, now doesn't blow either..... haven't hooked the trailer up yet, to see if it is powering out if manually manipulated....Will do so tomorrow.....so the Question is.... does the trailer brake box ITSELF..... have a brake pedal "power in" from the pedal switch short inside it?? Is this possible?? anyone ever have one/see this before?? Thanks! hank
Posted 2011-12-29 11:11 PM (#139733 - in reply to #139719) Subject: RE: Brake fuses blowing like a dead short....
Expert
Posts: 5870 Location: western PA
If you cut the red power wire to the controller, chances are the manual override won't work.
If the red wire is not cut, and a manual application also blows the fuse, you may have a truck wiring short to ground. Remove the BLUE wire from the controller to the brakes, and see if the fuse blows. If it doesn't, the truck wiring is probably grounded. If the fuse again blows, it is probably the controller. If the short is resolved by cutting the B+ wire, the controller may be at fault with an internal ground.
If I read your thread correctly, you said the problem occured even when the trailer was disconnected?
I had the same problem a few years ago, and resolved the problem with the installation of a new controller. With only four wires to contend with, it is a fairly easy time to trouble shoot the system, by temporarily sistering a second controller, without having to remove the original.
Posted 2011-12-29 11:30 PM (#139734 - in reply to #139733) Subject: RE: Brake fuses blowing like a dead short....
Member
Posts: 9
Location: Missouri
If the red wire, from the brake pedal isn't disconnected.. fuse instantly pops.. so can't test anything...with it DIS -connected... truck brake fuse doesn't blow.. and the brake box fuse doesn't blow....BOTH do otherwise...
Box (white wire) ground is solid... blue wire good all the way back.... black power wire ok.... all that's left is that red.... GOT to be a bad box... all TRUCK wiring NOW works 100%.. since the Box was cut/separated from truck brake light wiring...
Odd.. but when it comes to these things... a LOT of Odd stuff goes wrong!!
ALL this, is with the trailer NOT hooked up..... correct. Just the truck...
Brake fuses blowing like a dead short....
