A/C - System ID Prevents Evaporator Freeze Up
Classification:HA95-06
Reference:
NTB95-031
Date:
March 8, 1995
1993-94 240SX A/C SYSTEM WITHOUT THERMO CONTROL UNIT
APPLIED VEHICLE:
1993-94 240SX (S13)
SERVICE INFORMATION
When servicing a 1993-1994 240SX R134a air conditioning system, it is important to identify the correct system prior to parts replacement. Incorrect parts replacement may result in evaporator freeze-up.
If all components are correct on a thermo-less air conditioning system and evaporator freeze-up still occurs, replace the thermo control unit with 27675-53F00.
SYSTEM DIFFERENCES
Evaporator:
The thermo-less evaporator does not utilize a thermo control unit (thermistor). Although the cooling unit still has a thermo control unit mounted to it, this thermo control unit does not incorporate a thermistor, but only has a jumper wire inside.
Compressor:
The compressor used in the thermo-less system has a smaller minimum discharge capacity. This new discharge capacity provides freeze protection for the cooling unit.
NOTE:
The former compressor (92600-53F71) must not be used in place of the new compressor (92600-53F72). However, the new compressor may be used in place of the former.
Regarding A/C kit interchangeability, the former and the new A/C systems are fully interchangeable at the kit level. This is because the vehicle itself is not changed.
OPERATING CHARACTERISTICS:
In the thermo-less system, if the former compressor (larger minimum displacement) is used with the new cooling unit (no thermo control unit), possible evaporator freeze-up can occur.
When diagnosing an evaporator freeze up condition, first make sure the components (compressor & evaporator) are in accordance with the above interchangeability chart.
SERVICE PROCEDURE
Cooling Unit: If evaporator freeze-up occurs on a Thermo-less A/C system, replace the thermo control (black box), located on the evaporator case, with thermo control unit (P/N 27675-53F00).
COMPRESSOR:
If compressor replacement is required, use compressor (P/N 92600-53F72).