DESCRIPTION
The heater system delivers warm air to passenger compartment after engine warms up. The system draws in outside air, passes it through heater core and distributes it to various outlet vents. The system consists of circulation ducts, heater unit, blower assembly and heater control panel. (Scheme 1)
| WARNING | To avoid injury from accidental air bag deployment, read and follow all SERVICE PRECAUTIONS and DISABLING & ACTIVATING AIR BAG SYSTEM procedures in AIR BAG RESTRAINT SYSTEM article in the ACCESSORIES/SAFETY EQUIPMENT section. |
Scheme 1
HEATER ASSEMBLY
The heater assembly houses the heater core and mode doors. Coolant flowing into heater core is controlled by a heater valve mounted on side of heater assembly.
BLOWER ASSEMBLY
The blower motor forces outside air through heater assembly and into interior of vehicle. Operation of blower motor is controlled by fan control knob.
Fan Control Knob
Knob controls fan speeds to regulate amount of airflow. Fan can be operated at 4 different speeds.
Airflow 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.
Air Source Selector Lever
Lever controls intake of outside air or recirculation of inside air.
Temperature Control Knob
Knob controls blend-air door position. Depending on knob position, airflow is directed through heater core (hot setting), around heater core (cold setting) or through and around heater core, resulting in modulated temperatures between full hot and full cold. (Scheme 2)
Scheme 2
MODE CONTROL CABLE
Turn select knob to defrost setting. Connect damper cable with mode control link of heater unit at defrost position. Secure cable using clip. Check airflow selector knob operation. (Scheme 3)
Scheme 3
TEMPERATURE CONTROL CABLE
Turn select knob to maximum cold setting. Connect cable with temperature control link of heater unit at cold setting. Secure cable using clip. Check temperature control knob operation. (Scheme 4)
Scheme 4
AIR SOURCE CONTROL CABLE
Slide select lever to left. Connect control cable to blower assembly control link at the recirculation position. Secure cable using clip. Check air source selector lever operation. (Scheme 5)
Scheme 5
NO HEAT OR INSUFFICIENT HEAT
Blower motor inoperative. Engine coolant temperature low. Insufficient engine coolant. Insufficient engine coolant circulation. Clogged heater core. Airflow does not pass through heater core. Improper or disconnected duct connections.
CONTROL LEVER MOVES BUT MODE DOOR IS INOPERATIVE
Cable clip not properly installed. Defective control link on heater unit or blower assembly.
MODE DOOR POSITION INCORRECT
Defective control link on heater unit or blower assembly. Control cable not adjusted properly.
BLOWER MOTOR INOPERATIVE
- Check blower motor fuse in dash fuse/relay block. Check blower motor relay, blower motor resistor and blower switch. See «BLOWER MOTOR RELAY»(/acura/slx/i-1995-1999/remont/heater/#heater-system__blower-motor-relay) , BLOWER MOTOR RESISTOR and BLOWER SWITCH under TESTING. If blower motor fuse, relay, resistor and switch are okay, check blower motor. See «BLOWER MOTOR»(/acura/slx/i-1995-1999/remont/heater/#heater-system__blower-motor) under TESTING.
- If blower motor is okay, start engine. Turn on blower fan. Check voltage at Blue wire terminal of blower motor harness connector. If battery voltage is not present, repair open Blue wire between blower motor fuse and blower motor harness connector.
- If battery voltage exists, check for poor ground or open circuit in Blue/Black wire between blower motor and blower resistor harness connectors. Also check Black wire between blower switch harness connector and body ground.
BLOWER MOTOR INOPERATIVE IN CERTAIN POSITIONS
- Check blower motor resistor. See «BLOWER MOTOR RESISTOR»(/acura/slx/i-1995-1999/remont/heater/#heater-system__blower-motor-resistor) under TESTING. If resistor is not okay, replace resistor. If resistor is okay, check blower switch. See «BLOWER SWITCH»(/acura/slx/i-1995-1999/remont/heater/#heater-system__blower-switch) under TESTING. If blower switch is okay, go to next step. If blower switch is not okay, replace heater control panel.
- If blower does not operate in low speed, check for open Blue/White wire between blower motor resistor and blower switch harness connectors. If blower motor does not operate in medium-low speed, check for open Blue/Yellow wire between blower motor resistor and blower switch harness connectors.
- If blower does not operate in medium-high speed, check for open Blue/Orange wire between blower motor resistor and blower switch harness connectors. If blower motor does not operate in high speed, check for open Blue/Red wire between blower motor resistor and blower switch harness connectors.
BLOWER MOTOR DOES NOT SHUT OFF
- Check blower switch. See «BLOWER SWITCH»(/acura/slx/i-1995-1999/remont/heater/#heater-system__blower-switch) under TESTING. If blower switch is not okay, replace heater control panel. If blower switch is okay, check following wiring harness for short circuits.
- Check Blue/Black wire between blower motor resistor and blower motor harness connectors. Check Blue/Red wire between blower motor resistor and blower switch harness connectors. Check Blue/Orange wire between blower motor resistor and blower switch harness connectors.
- Check Blue/Yellow wire between blower motor resistor and blower switch harness connectors. Check Blue/White wire between blower motor resistor and blower switch harness connectors.
TESTING
| WARNING | To avoid injury from accidental air bag deployment, read and follow all SERVICE PRECAUTIONS and DISABLING & ACTIVATING AIR BAG SYSTEM procedures in AIR BAG RESTRAINT SYSTEM article in the ACCESSORIES/SAFETY EQUIPMENT section. |
BLOWER MOTOR RESISTOR
Disconnect resistor. Check resistance between indicated terminals. See BLOWER MOTOR RESISTOR TEST table. (Scheme 6) If resistance is not as specified, replace resistor.
| Terminal No. | Ohms |
|---|---|
| 1 & 2 | 2.4 |
| 2 & 4 | 0.9 |
| 2 & 6 | 0.28 |
| 2 & 3 | 0 |
BLOWER MOTOR RESISTOR TEST
Scheme 6
BLOWER SWITCH
Disconnect blower switch connector. Check continuity between indicated switch terminals. See BLOWER SWITCH TEST table. (Scheme 7)
| Switch Position | Continuity Between Terminal No. |
|---|---|
| 1 | 1, 2 & 4 |
| 2 | 1, 4 & 5 |
| 3 | 1, 3 & 4 |
| 4 | 1, 4 & 6 |
BLOWER SWITCH TEST
Scheme 7
BLOWER MOTOR
Disconnect 2-pin connector from blower motor. Connect positive battery terminal to Blue wire terminal. Connect negative battery terminal to Blue/Black wire terminal. Ensure blower motor rotates. Replace motor if it does not rotate.
BLOWER MOTOR RELAY
- Disconnect blower motor relay from dash fuse/relay block. With an ohmmeter, check for resistance of 85-105 ohms between relay terminals No. 1 and 3. (Scheme 8)
- Check continuity between terminals No. 2 and 4. Continuity should not exist. Apply battery voltage between terminals No. 1 and 3. Ensure continuity exists between terminals No. 2 and 4 with voltage applied. Replace relay if continuity is not as specified.
Scheme 8
REMOVAL & INSTALLATION
| WARNING | To avoid injury from accidental air bag deployment, read and follow all SERVICE PRECAUTIONS and DISABLING & ACTIVATING AIR BAG SYSTEM procedures in AIR BAG RESTRAINT SYSTEM article in the ACCESSORIES/SAFETY EQUIPMENT section. |
- Disconnect negative battery cable. Remove 4 attaching screws, disconnect switch connector and remove front console. Remove 3 screws, unplug connectors and remove lower cluster. Remove glove box. Remove 7 screws and one clip, and remove passenger's side lower instrument panel cover. Remove passenger's side knee bolster.
- Remove hood release handle. Remove driver's side lower instrument panel cover screws and clip. Release 3 fasteners from top edge and one from lower right bottom of driver's side lower instrument panel cover. Remove bolt from left bottom and clip from left side of lower instrument panel cover, and remove cover. Remove driver's side knee bolster.
- Remove defroster grille. Remove 2 bolts from safety restraint system adjusting bracket and cross beam under passenger's air bag module. Disconnect control cables from heater unit. Unplug instrument panel wiring harness connectors. Remove ground cable bolt from center bracket.
- Remove 6 bolts and 3 nuts securing instrument panel assembly. (Scheme 9) Remove passenger's air bag module. Remove 5 screws and release 4 fasteners from instrument panel top edge. Unplug wiring harness connectors, and remove instrument panel assembly. To install, reverse removal procedure.
Scheme 9
- Disconnect negative battery cable. Drain engine coolant, and disconnect heater hoses from heater unit. Remove instrument panel. See «INSTRUMENT PANEL»(/acura/slx/i-1995-1999/remont/heater/#heater-system). Disconnect resistor connector at blower assembly. (Scheme 1) Remove blower assembly duct.
- Remove Powertrain Control Module (PCM). Remove instrument panel support. Remove front console. Remove rear heater duct and heater unit. Remove driver's lap vent nozzle from bottom front of front heater unit. Remove duct from bottom of front heater unit. (Scheme 10) Remove mode control case, but DO NOT disconnect control link. Separate temperature control case, and remove heater core. To install, reverse removal procedure. Check mode door operation.
Scheme 10
- Disconnect negative battery cable. Remove instrument panel. See «INSTRUMENT PANEL»(/acura/slx/i-1995-1999/remont/heater/#heater-system) . Disconnect resistor connector. Remove blower assembly duct. Remove dash side trim panel. Disconnect blower motor connector. Remove blower assembly.
- Remove blower assembly screws and blower motor assembly. Remove clip and fan from assembly. Separate motor case, and remove blower motor. To install, reverse removal procedure.
