DESCRIPTION
The heater system consists of a blower and air inlet assembly, heater assembly, heater control assembly and heater valve assembly.
BLOWER & AIR INLET ASSEMBLY
The fresh air inlet door is used to select either fresh air from outside or recirculated air. Setting the Recirc/Fresh control lever to the "FRESH" position will allow outside air to enter. Setting the Recirc/Fresh control lever to the "RECIRC" position will allow inside air to recirculate. The air blend door is always open and admits recirculated air regardless of the position of the fresh air inlet door.
HEATER ASSEMBLY
The heater assembly houses the heater core, diverter door and defroster door. The heater core's coolant flow is controlled by a heater valve which is located on the left side of the blower motor assembly.
MODE LEVER
The mode lever controls the airflow air doors (defrost, heat and vent).
On setting the lever to the "VENT" position, air flows from the registers. Setting the lever to the "BI-LEVEL" position allows air flows to the registers, to the floor outlets and to the defroster outlets.
On moving the lever to the "HEAT" position, air flows to the floor outlets and to the defroster outlets. Moving the lever to the "DEFROST" position allows air to flow to the defroster outlets.
TEMPERATURE LEVER
This lever sets position of blend-air door to direct flow of air through heater core (HOT position), around heater core (COLD position), or mixture of both (modulated temperature between full HOT and full COLD).
System Operation Schematic. Scheme 1
Mode Control Cable Adjustment. Scheme 2
Exploded View of Heater Unit. Scheme 3
MODE CONTROL CABLE
To adjust, remove clamp from mounting boss. Set tube in clamp groove and cable in mode cam pin. Fix cam pin at lowest position. Set mode control lever just above "DEFROST" position. Lever should be.32" (8 mm) from the left furthermost point of travel. Secure tube clamp. (Scheme 2)
TEMPERATURE CONTROL CABLE
To adjust remove clamp from mounting boss. Set tube into clamp groove. Insert cable to heater valve control arm pin. Move heater valve control arm to fix heater valve control arm pin at highest position. Set temperature control lever just below "DEFROST" position. Lever should be.32" (8 mm) from the left furthermost point of travel. Secure tube clamp. (Scheme 4)
Temperature Control Cable Adjustment. Scheme 4
RECIRC/FRESH CONTROL CABLE
Remove clamp from mounting boss. Move tube toward Recirc/ Fresh arm pin and put tube inside of clamp. Move Recirc/Fresh control arm fully backward and secure Recirc/Fresh control lever to "RECIRC" position. (Scheme 5) Recirc/Fresh control lever should have a travel distance of 2" (53 mm).
RECIRC/FRESH Control. Scheme 5
Trouble Shooting Chart. Scheme 6
BLOWER SWITCH
Operate switch to check continuity. (Scheme 9)
| Switch Position | Continuity Between Terminals |
|---|---|
| LOW | B-C, C-1 |
| MED/LOW | B-C, C-2 |
| MED/HIGH | B-C, C-3 |
| HIGH | B-C, C-4 |
BLOWER SWITCH CONTINUITY
Blower Switch Connector. Scheme 7
MODE CONTROL LEVER
Place mode control lever in "DEFROST" position. Make sure air flows from defroster ducts. Place mode lever in "HEAT" position; air should flows from heater outlet. With mode control lever in "VENT" or "BI-LEVEL" position, ensure air flows from registers.
TEMPERATURE CONTROL
Place temperature control lever in "COLD" position. Position heater valve shaft in fully closed position. Ensure valve opens fully with temperature control lever in "HOT" position.
FRESH AIR INLET DOOR
Move Recirc/Fresh control level to "RECIRC" position. On blower unit, ensure door is completely closed when control lever is in "RECIRC" position.
Removal
- Remove steering wheel and steering column shroud. Remove glove box. Remove steering column shroud undercover. Remove lower instrument panel cover. Remove hood release handle mounting screws.
- Remove side lower instrument panel and disconnect connector. Remove cigar lighter and ashtray. Remove main lower instrument panel and disconnect connector. Remove cluster housing and disconnect switch connector. Remove illumination lamp. Remove cluster assembly. Disconnect the speedometer cable and electrical connectors.
- Remove cassette player and radio. Disconnect heater control wire from heater and blower unit. Remove instrument panel mounting bolts at heater bracket. Remove screw covers from upper instrument panel and unscrew screws. Remove instrument panel.
Installation
To install, reverse removal procedure.
Remove instrument panel. See INSTRUMENT PANEL in this section. Remove side defroster hose. Disconnect vent hose. Remove side register louver. Remove side defroster nozzle and side register louver nozzle. Remove instrument panel upper cover. Remove defroster nozzle. Remove heater connection. Remove center register louver duct. (Scheme 9)
To install, reverse removal procedure.
REAR HEATER DUCTS
Removal
Remove front seat. Remove supplement and main console (if equipped). Remove rear heating joint duct and rear heating duct. (Scheme 9)
To install, reverse removal procedure.
- Disconnect negative battery cable. Set temperature control lever to "HOT" position and drain coolant. Remove heater hose.
- Remove lower dash pad. Remove supplement console and computer (if equipped). Loosen rear heating duct mounting screw. Push rear heating joint duct and pull at heating duct. (Scheme 3)
- Disconnect heater control cable. Remove A/C unit (if equipped) or blower-to-heater duct. Loosen heater mounting bolts and remove heater unit.
Ventilators & Heating Duct Removal. Scheme 8
Check link mechanism for operation. Check heater core for clogging or coolant leakage. Check heater valve for operation and clogging. To install, reverse removal procedure.
Disconnect battery ground cable and wiring at blower motor. Remove retaining screws. Pull out blower motor. Remove retaining clip holding fan to motor and remove fan.
To install, reverse removal procedure.
Disconnect battery ground cable. Remove heater unit. Remove cable from control panel.
To install, reverse removal procedure. Inspect cable and mode cam to ensure they are in good working condition. See ADJUSTMENTS in this article.
Disconnect battery ground cable. Remove heater control panel. Remove cable from heater control panel. See ADJUSTMENTS in this article.
To install, reverse removal procedure. Inspect cable, temperature control arm pin and temperature control arm. See ADJUSTMENTS in this article.
Disconnect battery ground cable. Remove heater control panel. Remove cable from heater control panel.
Installation
To install, reverse removal procedure. Inspect cable, Recirc/ Fresh mode pin and Recirc/Fresh control arm. See ADJUSTMENTS in this article.
Excel Heater Wiring Diagram. Scheme 9
See also:
• INSTRUMENT PANEL