Operation CHARM: Car repair manuals for everyone.

Evaporator Core: Service and Repair

Fig. 16 Evaporator-heater retaining nuts. Horizon & Omni:





1. Drain coolant and discharge A/C system. Disconnect battery ground cable.
2. Disconnect heater hoses from core and plug core outlets to prevent coolant spillage.
3. Disconnect vacuum lines from intake manifold and water valve.
4. Refer to "H-valve, replace" procedure and remove H-valve.
5. Remove drain tube and evaporator heater assembly to dash retaining nuts.











6. Disconnect temperature control cable from evaporator housing.
7. Remove glove box.







Fig. 15 Removing center distribution duct & cover assembly. Horizon & Omni:





8. Working underneath instrument panel, disconnect vacuum harness from heater A/C control. Disconnect blower motor wire.
9. Remove the 7 screws holding right trim bezel to instrument panel. Beginning at right, swing trim bezel clear of instrument panel and remove.
10. Remove center distribution duct (1 screw at left center A/C outlet opening and 2 at rear edge of distribution duct).
11. Remove panel support bracket and right side lower cowl panel.








Fig. 17 Evaporator-heater assembly. Horizon & Omni:





12. Remove right side instrument panel pivot bracket screw.
13. Remove lower instrument panel screws at steering column.
14. Pull carpet back as far as possible from under evaporator heater assembly.
15. Remove nut from evaporator heater assembly to plenum mounting brace and blower motor ground cable. Support assembly and remove brace from stud.
16. Lift assembly and pull rearward as far as possible to clear dash panel and liner. Have assistant pull lower instrument panel rearward to allow enough clearance.
17. Carefully lower assembly, taking care to prevent studs from catching in dash liner.
18. With assembly on floor, slide rearwards until instrument panel is cleared.
19. Place evaporator heater assembly on bench and remove 1/4 -20 nut from mode door actuator arm on top cover. Remove 2 retaining clips from front edge of cover.
20. Remove mode door regulator by removing 2 screws holding actuator to cover.
21. Remove 15 screws holding cover to assembly and lift off cover.
22. Remove screw from heater core retaining bracket and remove heater core.
23. Remove H-valve and seal bracket screw from under H-valve sealing plate, and lift evaporator core out.
24. Reverse procedure to install.