GM Service Manual Online
For 1990-2009 cars only

Engine Control Module (ECM)

Scan Tool Output Control

Additional Menu Selection(s)

Description

Fan Relay 1

Special Functions/Output Control/Cooling Fan

Turns ON the cooling fan low relay. The normal commanded state of the fan relay is NONE. The ECM allows cooling fan relay control when the ignition is ON and the engine is OFF.

Fan Relays 2 and 3

Special Functions/Output Control/Cooling Fan

Turns ON the cooling fan high and cooling fan control relays. The normal commanded state of the fan relays is NONE. The ECM allows cooling fan relay control when the ignition is ON and the engine is OFF.

Fan Relays 1, 2 and 3

Special Functions/Output Control/Cooling Fan

Turns ON the cooling fan low, cooling fan high and cooling fan control relays. The normal commanded state of the fan relays is NONE. The ECM allows cooling fan relay control when the ignition is ON and the engine is OFF.

Fan Low

Special Functions/Output Control/Cooling Fan

Turns ON the cooling fan low relay. The normal commanded state of the fan relay is NONE. The ECM allows cooling fan relay control when the ignition is ON and the engine is OFF.

Fan High

Special Functions/Output Control/Cooling Fan

Turns ON the cooling fan low, cooling fan high and cooling fan control relays. The normal commanded state of the fan relays is NONE. The ECM allows cooling fan relay control when the ignition is ON and the engine is OFF.