Midwestdrifter
Engineer In Residence
Two things will cause the fan to run, the pressure sensor being disconnected or out of range (its on the high side line, near the firewall?) I would check to make sure the shop didn't unplug it, or damage the wires.
Or the ATC not getting CAN communication from the ECM. With the AC off, and the ignition on, the fan should not run. if it does, it means a CAN communication problem.
You can bypass the ATCs control of the clutch. DO NOT run the clutch with the cabin fan off. Do not run in ambient temps under 60F. DO not run the clutch if the condenser fan is not running. Normally the ATC will turn the condenser fan on if the pressure gets high enough (215psi?). its okay to have the aux fan not running on the highway, in stop and go traffic the pressure may get too high without extra cooling, and damage the compressor.
Or the ATC not getting CAN communication from the ECM. With the AC off, and the ignition on, the fan should not run. if it does, it means a CAN communication problem.
You can bypass the ATCs control of the clutch. DO NOT run the clutch with the cabin fan off. Do not run in ambient temps under 60F. DO not run the clutch if the condenser fan is not running. Normally the ATC will turn the condenser fan on if the pressure gets high enough (215psi?). its okay to have the aux fan not running on the highway, in stop and go traffic the pressure may get too high without extra cooling, and damage the compressor.
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