My new daily driver. 1984 dodge rampage

not sure how to test the temp switch. One side of the connector is grounded. When it reaches the correct temp it's suppose to complete the circuit and send ground out to though the other wire.[/QUOTE]

Unplug the switch when engine is cold, not running. Probe the contacts with an ohmmeter. Should read open.

Start the car and get it fully warmed up then check the contacts, should read full continuity when the switch closes.

Its just a bimetal spring with contacts inside. When it gets hot enough they close.