On two wire connectors (single speed fans), apply battery voltage to one
of the terminals on the fan connector and ground the other one.
Fig. 1: Fan testing connections for two wire units
Fig. 2: Fan testing connections for four wire units
(two speed fans)
On four wire connectors (two speed fans), apply battery voltage to two terminals
and ground the other two. This will check the high speed mode of the fan,
to check the low speed connect the wires the same as two wire models.
Attach an ammeter inline on the positive wire.
The fan should operate, if not, replace the fan assembly.
If the fan operates when battery voltage is applied, but not when connected
to the vehicle, check the cooling fan relay and/or the engine coolant temperature
sensor.
While the fan is operating, the current draw should be as follows:
