I’m having a problem concerning a dump trailer I haul. The battery won’t get fully charged after dumping a few loads. I was told that was because the 7 pin plug, even though it has a 12v line is only conducting a trickle charge. Was also told that in order for the battery to fully charge when being towed was to put a fuse in the fuse box. This a factory installed harness, not an aftermarket on. The vehicle is a 98 dually which I have owned since it was new. Any help will be greatly appreciated.

Mike

 

there was a similar thread about a month ago where a guy was melting wires and plugs. he'd identified the wire size at 14 or 16 gauge and measured how long it was and how much resistance and how much amps it was actually carrying. he was putting in bigger fuses and melting more wires and generally not having any luck.

based on the wire and fuse size, i'd say the factory harness is only designed to run some small lights or something on the trailer, not to charge a battery. to do that, you'd have to run full size battery cable, and have a heavy duty connector. you'd probably also want some kind of RV type battery isolator, so you protected your truck battery from discharge.