I suppose it’s not necessary to leave the wiring until last, but I have chosen to do so. The wiring process is very simple if you’re only installing the kit. The kit comes with two crimp-type wire connectors, a switch, and a length of red wire. One of the two wires on the conversion kit solenoid is a ground wire and the unit is meant to be grounded via one of the bolts that mounts the kit to the bed. The other one is the positive voltage to energize the solenoid.
Find a source of engine-on-only power somewhere, either under the dash or under the hood. Just turn the key on to the run position, and ground your test light. Poke around at electrical connections until you find one that’s lights up the test light. Turn off the key and check the connection again. If there’s no voltage present, you’ve found your power source. I chose to connect to a solenoid under the hood.
I’m a little bit hyper about my wiring connections because there’s no problem more maddening to find than an intermittent ground or something like that. For that reason I don’t like crimp connectors and I loathe Scotchloks. I’m a big fan of solder and heat shrink tubing wherever I can use it, especially when the connection might be exposed to the weather. I also like ground connections to be made under the hood, at least. I’ve seen some body grounds get pretty unreliable as the vehicle ages and rusts, especially grounds toward the rear of the vehicle. But the body grounding under the hood is usually pretty decent. So I chose to solder and heat shrink all my connections at the conversion kit in the bed, and ground my circuit to an existing body ground on the firewall of the truck. I elected to use the crimp connectors under the dash, and to connect the wire to the fittings under the hood.