I bought a new sending unit for my idiot light but the temp light's still not coming on with the ignition on or any other time. A manual told me to remove the wire and ground it, then the light should come on, which it does. I don't get it. Would love some help with this (yes I know I need a gauge!).
Make sure you don't use teflon tape or anything else that would insulate the switch from ground. The switch is nothing but a contact the closes when the engine temperature gets above the setpoint. Make sure you didn't get a sender for use with a temperature gauge. Stick on ohmmeter on the center terminal of the switch and make sure you have infinite resistance (open circuit)