Join Date: Apr 1999
Location: Chugiak Alaska
Feedback Score: 0 reviews
Good chance your trailer plug is always hot. See if you are getting 12 Volts to the plug when the key is off. Buddy had a trailer that kept draining the battery because he had a inverter that was hooked to the fridge. Look for a extra wire coming of the positive side of either battery and trace it out. Relay could be stuck closed (I have not seen that, but could happen I guess). I had a 99 F350 that did not come with the factory relay plug/ harness. The previous owner just ran a hot wire from battery to trailer plug.
Early 1999 F350 AUTO 4x4 CC LB DRW 4.10 6.0 trans cooler, Front hitch, 2,000 hubs/ brakes, Bilstein shocks/steering stabilizer, Diesel site coolant filter 203 thermostat, EBV delete, new O-rings, new Oil cooler, RIFF RAFF FRX, Glow plug led, Pillar gauges, Lighted cupholder, Painless wiring fuze block, Harpoon/hutch mods, Removed axle blocks. Air bags, 5 wheel hitch, In bed 7 pin plug. Spare tire key delete. KLHANSEN on speed dial. 75,000 as of May 2019