GM 89018270
Evaporator Core

Start servicing or repairing evaporator core by disassembling heater/vent module due to the need to remove heater/vent module screws and detach the module. The evaporator core must be separated from the heater/vent module after the components are separated. After placing the evaporator core inside the heater/vent module one should reassemble its component halves while following the Fastener Notice mentioned in the Service Precautions. Reinstall the heater/vent module after securing its screws to 1.6 Nm (14 lb in). The final step includes evacuation and recharging of the A/C system followed by leak testing the component fittings under J 39400-A.

The first step when replacing the evaporator core requires drainage of engine coolant and collection of the refrigerant from the A/C system. Begin by unscrewing the module screws which attach the heater/vent module and then separate the module pieces. Reinstall the new evaporator core in the heater/vent module after removing it from the module. Assemble the module halves following the Fastener Notice to achieve proper assembly. Securely fasten the heater/vent module screws using 1.6 Nm of torque which equals 14 pounds of inch and reattach the module. The conclusion involves engine coolant refilling and evacuation and recharging of the A/C system.

The initial step for Evaporator core replacement of the auxiliary hvac module requires refrigerant removal from the a/c system and subsequent drainage of engine coolant. The auxiliary hvac module under the vehicle requires disconnecting of heater lines (2,3) and air conditioning lines (2,3). The auxiliary hvac module needs its vehicle securing nuts removed before safety stands can be taken off the vehicle and the platform should be lowered. Afterwards start by removing both the real time damping (RTD) module with its electrical connectors and the right rear quarter trim panel. Then remove the fastener that attaches the upper auxiliary air duct while sliding the duct into place near the headliner. Take out the rear auxiliary hvac module by removing its fasteners and position it on a work surface. Start by removing the air temperature actuator and Heater Core cover as well as Heater Core and lower module cover from the module before removing the Evaporator core from the lower module cover. Put the Evaporator core inside the lower module cover and reassemble everything by inserting the lower module cover, Heater Core, Heater Core cover and air temperature actuator onto the module. Install the auxiliary hvac module assembly back into the vehicle while fastening it using two bolts which should be inside the vehicle body. To finish the installation process, connect the upper auxiliary air duct to the air distributor duct through fastener attachment. After that, reinstall the rtd module and right rear quarter trim panel together with electrical connector reattachment. Reposition the vehicle at its height before installing auxiliary hvac module nuts while twisting them to achieve 9 n.m (80 lb in). Broaden and join (2,3) air conditioning lines with nut to the auxiliary hvac module while using a torque of 16 n.m before linking heater lines to the module. Lower the vehicle and follow the system with correct fluid and then complete a refrigerant recharging process.

The first step to replace an evaporator core involves removing the heater/vent module after screw removal followed by separating the module parts. Moving forward with the replacement remove the evaporator core from the heater/vent module. The installation requires placing the new evaporator core inside the heater/vent module followed by module half assembly with strict adherence to the Fastener Notice in Service Precautions. Install the heater/vent module by screwing the components until they are tightened to 1.6 Nm (14 lb in). Evacuate and recharge the A/C system then test for leaks on the component fittings by using tool J 39400-A.

Before starting Evaporator core replacement on the auxiliary hvac module, technicians should recover a/c system refrigerant and drain engine coolant. Begin by raising the vehicle and disconnecting the heater lines from the auxiliary hvac module that is located underneath the vehicle. Then follow this step with removing the air conditioning lines from the same module. Unscrew the nuts holding the auxiliary hvac module to the vehicle structure after which you can remove safety stands from under the vehicle where you can lower it to the ground. You should start by removing the right rear quarter trim panel along with the real time damping (RTD) module then disconnect all electrical connectors when necessary. Proceed by disassembling the fasteners from the upper auxiliary air duct and lower auxiliary outlet duct and air distributor duct before extracting the rear auxiliary hvac module to work on a stable surface. Disassemble the air temperature actuator alongside the stud connecting Heater Core input and output pipes followed by skilled detachment of the module case gasket from the Heater Core pipes. Next separate the Heater Core from the clamp and rear hvac module lower cover after keeping the existing gasket available for reuse. The installer separates the front case from the back half and removes the Evaporator core from the back section for gasket and seal evaluation with necessary replacements. The assembling process includes moving the thermal expansion valve (TXV) to the new Evaporator core then installing both components with the Evaporator core seal while ensuring correct placement of air distributor duct gasket and temperature door during this operation. Case halves should be put together while also connecting the Heater Core and managing its clamp and the rear hvac module lower cover. After securing both bolts the vehicle receives the auxiliary hvac module, air temperature actuator and Heater Core pipe retainer and gasket and stud. Reassemble the air distributor duct and the lower auxiliary air outlet together with the upper auxiliary air duct by joining electrical connectors and rtd module. The vehicle needs to be raised for securing the auxiliary hvac module through the use of nuts which require a torque of 9 n.m (80 lb in). Link the air conditioning connectors followed by tightening the nut to 16 n.m (12 lb ft), then resume heater line operation. Proceed with fitting engine coolant before recharging the refrigerant then perform fitting leak detection with the halogen leak detector (J 39400-A).

Take out the stud located on the underside of the rear HVAC module between the heater core inlet and outlet pipes.

Reconnect the air conditioning lines and nut to the auxiliary HVAC module, tightening the nut to 16 N.m (142 lb in), then connect the heater lines at the underside of the vehicle.