All my electrical woes.

The factory radio has two, 2-wire pigtails on it. One with a T connector with the red w/tracer (12V+) and an the other is an orange wire for the dial light. The other pigtail has the 2 speaker wires. The gauge problem is most likely the voltage limiter built into the fuel gauge but I'd check to be sure that power is getting to the gauge first and that there is a pulsing 5V leaving the gauge at the middle post under that plastic cap. Redfish has a kit to convert to a solid state limiter that you can buy or have him convert your gauge. The heater motor can be hot wired to see if it works or not. Just run a 12V+ wire direct from the battery to the motor + lead. I like to see what kind of amperage it's drawing to as they can melt the wiring and switches if they're drawing too much.