TEMPERATURE CONTROL KNOB
Control knob opens and closes heater control valve, regulating heat output. Highest heat output is obtained when selector knob is turned clockwise to warm setting. When temperature knob is turned to cool setting, ambient air is used for ventilation.
FRESH/RECIRCULATED AIR SELECTOR LEVER
This lever is used to select source of airflow. With lever at fresh air setting, outside air is allowed to enter and/or pass through heater. With lever at recirculated air setting, inside air is recirculated through passenger compartment.
BLOWER SWITCH
The blower can be operated at different fan speeds to regulate amount of air forced through vehicle. Fan speed will increase as switch is turned to the right.
MODE SELECTOR KNOB
Depending on position selected, airflow can be directed to different areas of passenger compartment. Airflow selection capabilities include individual areas or a combination of windshield, upper body, knee and/or foot area.
Scheme 1
TEMPERATURE CONTROL CABLE
Position temperature control knob at warm setting (extreme right). Move blend-air damper lever completely downward, in direction of arrow, and connect inner wire of temperature control cable to damper lever. (Scheme 2) Secure outer wire of control cable using clip.
Scheme 2
AIR SELECTOR CABLE
Position fresh/recirculated air selector knob at recirculated air setting. Move air selector damper lever in direction of arrow until in contacts stopper. (Scheme 3) Connect inner wire of air selector cable to damper lever. Secure outer wire of selector cable using clip.
Scheme 3
MODE SELECTOR CABLE
Place mode selector lever at defrost setting. Move mode selector damper lever in direction of arrow, and connect inner wire of mode selector cable to damper lever. (Scheme 4) Secure outer wire of selector cable using clip.
Scheme 4
BLOWER INOPERATIVE
Blown fuse. Blower motor improperly grounded. Defective switch, blower motor relays or resistor.
INSUFFICIENT HEAT
Obstructed heater outlet. Blend-air damper improperly adjusted. Defective thermostat. Obstructed heater hoses. Control cables improperly adjusted. Plugged heater core. Mode selector dampers improperly adjusted.
NO VENTILATION
Mode selector cable incorrectly installed. Ducts crushed, bent, clogged or improperly connected.
BLOWER MOTOR SWITCH
Using ohmmeter, check continuity between indicated terminals. See BLOWER MOTOR SWITCH CONTINUITY table. (Scheme 5)
| Switch Setting | Continuity Between Terminal No. |
|---|---|
| Low | 1 & 8, 3 & 5 |
| Medium-Low | 1 & 8, 5 & 6 |
| Medium-High | 1 & 4, 1 & 8, 2 & 5 |
| High | 1 & 4, 1 & 8, 5 & 7 |
BLOWER MOTOR SWITCH CONTINUITY
Scheme 5
BLOWER MOTOR
Apply battery voltage directly to blower motor terminals. Ensure blower motor operates smoothly. Reverse polarity, and ensure motor operates smoothly in the reverse direction. Replace motor if it does not function as indicated.
BLOWER MOTOR RELAYS
- Remove blower motor relays from fuse/relay block and blower case. Using ohmmeter, check continuity of each relay. Check continuity between terminals No. 1 and 3. (Scheme 6) Continuity should not be present.
- Check continuity between terminals No. 2 and 4. Continuity should be present. Connect 12-volt battery to terminals No. 2 and 4. (Scheme 6) Ensure continuity exists between terminals No. 1 and 3 with battery voltage applied. If continuity is not as specified, replace defective relay.
Scheme 6
BLOWER MOTOR RESISTOR
Disconnect harness connector from resistor, located behind glove box upper cover. Using ohmmeter, check resistance between indicated terminals. See BLOWER MOTOR RESISTOR RESISTANCE table. (Scheme 7) If resistance is not as specified, replace resistor.
| Terminal No. | Ohms |
|---|---|
| 2 & 1 | 1.79-2.06 |
| 2 & 3 | 0.38-0.44 |
| 2 & 4 | 1.10-1.26 |
BLOWER MOTOR RESISTOR RESISTANCE
