Spal fan Problems

The temp sending unit actually grounds the circuit to complete it.

You are using a relay? The gray wire from the relay goes to the sending unit, the orange wire goes to switched ignition, the big red wire goes to the fan, the big yellow wire goes to the battery voltage.

If you are not using a relay, you stand a chance of burning the wires up, as those fans have a lot of amp draw.

If everything is wired correctly, you can simply ground out the sending unit wire, and the fan should come on.

Disconnect the grey wire from the sending unit and touch it to ground with the key on (engine not running).

If the fan runs, the sending unit is bad or not getting a ground (too much teflon tape?)

if it doesn't run:
Listen for the relay clicking.
If it clicks, get a voltmeter or test light and check for battery power at the fuse and relay yellow wire.

If good, check the wires and connection to the Red (fan) wire and the Black Fan ground wire. Put battery power directly to the red wire - still no fan, possible bad fan motor.

If no relay click, check for ignition power at the orange wire. Possible bad relay

diagram:



Good luck and have fun.