2001 cooling fans

[robertr1249]

Not sure if my cooling fans are operating properly. My a/c outlet temp out of the dasnboard rises significantly when the van is at idle or not moving. Do the cooling fans normally turn on immediately when the a/c is turned on or I've also heard they only come on when the a/c head pressure is above 175 psi. Can someone tell me which is the case?? Thanks

 

[sergeimoskva]

Hi !
There are three basic modes for the fans: OFF, Low-Speed, and High-Speed. These modes are controlled by the Powertrain Control Module (PCM).
Fans OFF:
When the coolant temperature is less than about 220 degrees F (104 degrees C) or
The A/C refrigerant pressure is less than 190 psi (A/C off).
Low-Speed:
When the coolant temperature is between about 220 degrees F (104 degrees C) and 230 degrees F (110 degrees C) or
The A/C refrigerant pressure is more than 190 psi (1310 kPa) or
When van is turned off and the coolant temp is more than about 284 degrees F (140 degrees C) and system voltage is more than 12 Volts. Fans will run for about 3 minutes.
High-Speed:
When the coolant temperature is above about 230 degrees F (110 degrees C) or
The A/C refrigerant pressure is more than 240 psi (1655 kPa) or
When certain DTCs are set.
Other information:
The thermostat for these vans normally opens at about 195 degrees F (93 degrees C)
The "Engine Coolant Temperature" message should appear (on dash) if the engine coolant temperature is above about 262 degrees F (128 degrees C). PCM sends a message to the Instrument Panel indicating temperature.
The "Engine Coolant Level" indicator should appear (on dash) if the coolant level goes below a certain level.

 

[robertr1249]

Thank You very much for the great explanation on the fans!!