Evaporator Case: Service and Repair

***THIS ARTICLE INCLUDES UPDATES MADE BY TSB #94-2-12, DATED JANUARY 26, 1994***

NOTE: Replace the evaporator core and housing assembly with a new assembly which has a relocated evaporator core that allows the condensate to drain into the sump area of the housing rather than into the passenger compartment. Refer to the following procedure for service details.

NOTE: Automatic Temperature Control (ATC) equipped units built before 7/1/92 will require a new aspirator assembly (F4SZ-19E628-A) along with the new evaporator case assembly.

CAUTION: Observe all safety and service precautions while performing the following service procedure.

1. Record radio stations.
2. Disconnect battery ground cable.
3. Remove steering column lower trim cover. (Remove three (3) screws at bottom, one (1) screw LH side and pull to disengage five (5) snap-in retainers across top).
4. Remove steering column lower opening reinforcement. Six (6) screws retain reinforcement to instrument panel.
5. Remove steering column upper and lower shrouds.
6. Disconnect wiring from steering column.
7. Remove shift interlock switch, if equipped.
8. Disconnect steering column lower universal joint.
9. Support steering column and remove four (4) nuts retaining column to support. Remove column from vehicle.
10. Remove one (1) nut retaining LH side of instrument panel to parking brake bracket.
11. Remove RH and LH side cowl trim panels.
12. Disconnect electrical connections at RH cowl side.
13. Remove two (2) instrument panel-to-floor tunnel nuts.
14. Open glove compartment door and depress both sides of glove compartment inward and lower glove compartment door toward floor.
15. Disconnect wiring, heater and A/C vacuum lines and control cables through glove compartment opening.
16. Remove two (2) screws at RH side retaining instrument panel to cowl side.
17. Remove two (2) screws at LH side retaining instrument panel to cowl side.
18. Remove RH and LH finish panel by pulling up to disengage snap-in retainers, three (3) on RH side and four (4) on LH side.
19. Remove RH and LH roof rail trim panels.
20. Remove four (4) screws retaining instrument panel to cowl top.
21. Gently pull instrument panel away from RH side of cowl panel.
22. Place a drain pan or suitable container under heater hose connections at the cowl panel.
23. Discharge refrigerant from the A/C system at service access gauge port valve located on suction line, following the proper recovery procedure.

CAUTION: Observe all safety precautions.

24. Disconnect the liquid line and the suction accumulator/drier inlet tube from the evaporator core at the cowl panel. Cap refrigerant lines and evaporator core to prevent the entrance of dirt and excess moisture.
25. Disconnect heater hoses from heater core tubes and plug hoses with suitable 5/8" (16 mm) and 3/4" (19 mm) plugs. Cap heater core tubes to prevent coolant loss from heater core during removal of evaporator core.
26. Disconnect vacuum supply hose from in-line vacuum check valve in engine compartment.
27. Working under the hood, remove three (3) nuts retaining the evaporator case to the cowl panel.
28. Inside the passenger compartment, remove the screw attaching the evaporator case support bracket to the cowl top panel.
29. Remove one (1) nut retaining the bracket below the evaporator case to the cowl panel.
30. Carefully pull the right end of the instrument panel away from the cowl panel, pull the evaporator case away from the cowl and remove the evaporator case from the vehicle. Place the evaporator case on a work bench.
31. Transfer the following parts from the removed evaporator assembly to the new service evaporator assembly, based on the type of system in the vehicle.

NOTE: If the unit is equipped with ATC and was built prior to 7/1/92, you will have to use a new aspirator (F4SZ-19E628-A) that is designed for the new service case and eliminate the old aspirator. Change over to the new aspirator as follows:
a. Transfer the gasket from the existing aspirator assembly plate to the back of the blower speed controller so you will seal the mating surface of the controller to the case. Install the blower speed controller to the case without the old aspirator, making certain that the gasket seals properly.
b. Discard the existing aspirator assembly and install the new aspirator (F4SZ-19E628-A) in the upper case half, in the existing hole next to the muffler assembly, using a screw (# 10-12x .75 hex washer head self-tapping); obtain locally.
c. Using the old aspirator connecting tube, cut it to size (shorten) and install it between the new aspirator and the muffler.

32. Cut off the end of the drain tube located on the bottom of the evaporator case under the heater core area.

Cut Off The End Of The Drain Tube, Do Not Drill.:

CAUTION: Do not drill out the hole because the heater core could be damaged, Figure 5.

Connect A Hose To The Drain Tube.:

33. Connect a 1/2" (12.7 mm) outside diameter hose (E8UZ-19K592-A) to the drain tube using a small hose clamp (376240-S100), Figure 6.
34. Install the evaporator case in the vehicle by reversing the removal procedure.
a. Drill a hole in the cowl panel to accommodate the new drain tube. See Figure 6 for location. The hole should be about 2" (50.8 mm) below the regular evaporator case drain tube.
b. After the new drain tube is through the hole and in permanent position, seal around the tube with body sealer (F1AZ-19562-A).
35. Recharge the A/C system and check the operation of the system.
36. Reset radio stations recorded in step # 1.

NOTE: Check the operation of all components after assembly is completed.

NOTE: If evaporator core and housing assembly is replaced per this TSB article, it will not be necessary to perform TSB 94-2-9.