Heater assembly is contained in a housing beneath instrument panel. Assembly consists of blower motor, heater housing and core, coolant valve, and control panel.
VENTILATION
Ventilation is a separate function from heating and is combined into the heating unit to accomplish fresh air ventilation when required. Separate selector lever, or position setting, on mode lever permits fresh air to enter passenger compartment. Blower switch position determines air flow volume.
MODE LEVER
Mode lever controls air flow air doors (intake, blend-air, heat, defrost and ventilation). Lever position on control panel determines the following door settings
Recirc/Fresh Door
In open position, outside air flows into heater system after passing through blower motor fan. In closed position, inside air is recirculated through heater system.
Ventilation Door
Permits fresh air flow out of instrument panel registers.
Defrost Door
Controls air delivery or defroster outlets when this mode is selected. This separate door opens when mode door closes off floor and instrument panel outlets to direct air to windshield.
Blend-Air Door
See TEMPERATURE LEVER operation.
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. The lever also controls opening and closing of water valve. In any position except cold, water valve is open, allowing engine coolant into heater.
FAN SWITCH
A separate sliding lever on control panel provides 4 fan speeds using a blower resistor.
RECIRC/FRESH CABLE
Set at recirc position. Connect cable to air intake door lever, then position door in its fully closed position. Push cable away from door lever to remove slack and secure with retaining clip.
BLEND AIR DOOR/TEMPERATURE CONTROL DOOR
- Set temperature lever to maximum cold position. With air mix door moved away from link lever, connect temperature control rod to link lever and clamp cable. (Scheme 1)
- Pull control rod of water valve in direction of arrow to obtain clearance of.08" (2.0 mm) between ends of rod and link lever. Connect rod to door lever. Check knob to see if knob moves smoothly
Scheme 1
MODE SELECTOR DOOR & HEAT-DEFROST DOOR
Set mode selector lever to defrost position. Connect control cable to side linkage while pushing linkage upward. Pull cable in opposite direction to remove slack and secure with retaining clip.
Note. After adjustments are complete, check all controls, doors, cables and rods for smooth and complete operation.
NO HOT AIR
Malfunctioning engine coolant thermostat. Heater core plugged. Low coolant level. Blend-air door malfunctioning. Heater valve not opening.
NO AIRFLOW TO FLOOR
Blower motor speed too low. Poor electrical connection. Blower switch or resistor faulty. Floor air door or floor air door actuator malfunctioning.
LOW AIRFLOW TO DEFROSTER
Floor/defroster door malfunctioning. Faulty door seal. Defroster nozzle plugged. Leaking duct-to-nozzle connection. Malfunctioning defroster door actuator.
HOT AIR AT ALL TIMES
Water valve not closing. Mode door malfunctioning. Mode door seal faulty.
NO BLOWER MOTOR OPERATION
Fuse blown or fusible link melted. Electrical lead to motor disconnected. Fan switch defective. Blower motor defective. Resistor defective. Defective blower relay (V6 models).
CONTROL LEVER DIFFICULT TO OPERATE
Inner wire rubbing on outer case end. Cable kinked or bent. Doors or lever sticking.
OUTSIDE AIR ENTERING WHEN FAN IS OFF
Air intake door misadjusted. Control cable misadjusted. Malfunctioning air intake door actuator.
BLOWER MOTOR/FAN NOISE
Loose bolt or foreign objects in blower fan. Broken blower fan blade(s).
HEATER CORE & ASSEMBLY
Note. Heater core REMOVAL & INSTALLATION procedures are not available from manufacturer. However, exploded views of the systems have been provided.
Removal & Installation
Disconnect battery. Disconnect blower harness connector. Disconnect control cable from air intake door. Remove blower motor retaining screws and take out blower motor. To install, reverse removal procedure.
Remove control cables by unfastening clamps at door levers. Disconnect harness connector. Remove heater control mounting bolts and remove heater control assembly. To install, reverse removal procedure. Adjust cables and check system operation.
Scheme 2
See also:
• TEMPERATURE LEVER