Temperature Switch Test

Disconnect temperature switch lead from distributor modulator valve and connect it to a test lamp with a good ground. Turn on ignition switch and warm temperature switch with hand or sponge saturated with hot water. Light should go on when switch temperature exceeds 65°F. If light does not go on, circuit is open or grounded or switch is faulty. Cool switch until it is below 49°F (an aerosol spray such as starting fluid should provide sufficient cooling), light should go out. If light does not go out, either it isn't cooled enough or switch is faulty.