Operation CHARM: Car repair manuals for everyone.

Cooling System: Description and Operation

Fans

How the Circuit Works
Voltage is provided at all times to the radiator fan relay contacts through fuse 57 (in the main under-hood fuse/relay box), and to the A/C condenser fan relay contacts through fuse 58 (in the main under-hood fuse/relay box). With the ignition switch ON (II) and the engine not cranking, voltage is provided to the coils of the relays through fuse 20 (in the under-dash fuse/relay box).

The relays are grounded the ECM. Grounding the relays energizes their coils and applies battery voltage to the radiator and condenser fan motors. Both fans then run until ground is removed from the relay coils.