GM Service Manual Online
For 1990-2009 cars only

Powertrain Control Module (PCM) or Engine Control Module (ECM) Scan Tool Output Controls

Scan Tool Output Control

Additional Menu Selection(s)

Description

Fan Relay 1

Output Control/Cooling Fan

The scan tool displays a Commanded State of Off or On. This allows you to communicate with the ECM and activate or deactivate the cooling fan 1 relay, manually turning both low speed fans On and Off.

Fan Relays 2 and 3

Output Control/Cooling Fan

The scan tool displays a Commanded State of Off or On. This allows you to activate or deactivate the cooling fan series/parallel relay and the cooling fan 2 relay. The RH cooling fan 2 turns ON and OFF in high speed.

Fan Relays 1, 2 and 3

Output Control/Cooling Fan

The scan tool displays a commanded state of OFF or ON. This allows you to activate or deactivate all of the cooling fan relays. Both cooling fans turn ON and OFF in high speed.