Fan Monitor (FANM)

FANM circuit is spliced into the Power-To-Low Speed Fan circuit. PCM monitors FANM circuit for diagnostic purposes. When cooling fan(s) is off, FANM circuit voltage is pulled low by path to ground through cooling fan.

With FANM circuit voltage low, PCM can verify FANM circuit and Power-To-Low Speed Fan circuit are complete from FANM splice through cooling fan to ground. This also confirms that circuits are not shorted to power.

When fan is on, voltage is supplied from CCRM to the appropriate Power-To-Fan and FANM circuit. With cooling fan on and FANM circuit high, PCM can verify fan control relay contacts in the CCRM are closed and that battery voltage is being supplied to the CCRM for the LFC and HFC relays. See CCRM circuit schematic in CIRCUIT TEST X in TESTS W/CODES article for more information.