Compressor Not Operating At Cold Temperatures (LI83.00-P-045021)

COMPRESSOR NOT OPERATING AT COLD TEMPERATURES

TECHNICAL SERVICE BULLETIN

COMPLAINT

AC compressor not operating at cold temperatures.

CAUSE

If the ambient temperature sensor value rises, vehicle speed is less than 13 mph and the coolant temperature is above 104° F; the control module 'freezes' the ambient temperature value. The purpose of this is to compensate for any measurement error of the ambient temperature due to heat radiated by the engine. The climate system continues to operate using this 'frozen' value until the engine coolant temperature drops below 104° F or vehicle speed exceeds 28 mph. Only when one of these two conditions is met is the actual value from the ambient temperature sensor used by the climate system for regulation. For control reasons, the AC compressor is not allowed to operate when the climate system is using this 'frozen' ambient temperature value or the ambient temperature is less than 37° F.

If a customer's concern is that the windows fogging under these conditions where the AC compressor is not operating, the following options are available.

REMEDY

1. Select Defrost on the climate control panel to defog the windows.
2. Operate the vehicle until the speed exceeds 28 mph and the engine coolant temperature is higher than 104° F. The refrigerant compressor will reactivated after these conditions have been achieved.

SYMPTOMS