Swapped 92 pickup keeps blowing fuses
 

I have a 1992 Sr5 3.4 swapped extended cab pickup. It has the Toyonly swap harness. It keeps blowing the tail light fuse. At first it only blew it when i started the truck. It's missing the two marker lights that are on the side of the headlights the passenger side wires sparked out on the bumper and that's when this problem started. Since then I've put another relay on it out of my standard cab and replaced both trail light bulbs. I've read around that it could be the radio dimmer so I pulled the dash apart and steered looking around. After I got my dash apart now the fuse blows as soon as I turn on my lights. My radio ground was connected to the dimmer, since that is also the ground wire, so I disconnected it and just grounded my ratio to a bolt. It's still blowing fuses as soon as I turn my lights on and I'm stumped besides maybe a pinched wire somewhere. I've never had a problem with the wiring on this truck until those two wires grounded on the bumper. Any ideas?

Chances are when your front marker lights shorted, the wires somewhere in the harness they melted and are now shorted to ground. Get a wiring diagram for your truck. figure out where all the wires go on that circuit and figure out where all the connectors are. Attach a test light to the fuse on the light side. Attach the power leg of the test light to battery positive. When you turn on the lights the test light should come on when shorted. Leave the switch on and starting at the lights disconnect all the connectors in the circuit. When the test light turns off you'll know where in the circuit the short is.