Heater System Chevrolet Camaro IV

DESCRIPTION & OPERATION

Fresh air enters system through air inlet at right end of instrument panel. Blower motor forces air through system. Temperature door controls air volume directed through heater core. Temperature door is controlled by a cable. Mode doors control whether air exits system from floor vents, face vents or defrost vents. Mode doors are controlled by vacuum motors.

Note. Equipped with driver-side air bag.

HEATER OUTPUT TEMPERATURE CHECK

Note. Perform this check if sent here from chart.

1. On V6, remove radiator cap when engine is sufficiently cool. On all vehicles, select heater (floor) mode, high temperature setting and high blower speed. Idle engine for about 20 minutes until warm (on V6, when coolant can be seen flowing in radiator, install radiator cap).
2. Drive vehicle at 30 MPH (48 KM/H), measuring ambient air temperature and floor outlet air temperature with accurate thermometers. If floor outlet air temperature exceeds minimum specification, heater output temperature is considered insufficient. See HEATER OUTPUT TEMPERATURE MINIMUM SPECIFICATIONS table.

HEATER OUTPUT TEMPERATURE MINIMUM SPECIFICATIONS

FUNCTIONAL TEST

Note. Perform this check if sent here from chart.

1. Idle engine for about 20 minutes until warm or until thermostat opens. Ensure coolant temperature is about 194°F (90°C). Select bi-level mode. Move temperature lever to coldest temperature setting. Select high blower speed. Air should exit all outlets and should be about the same temperature as outside air.
2. Select vent mode. Air should exit vent outlets and should be about the same temperature as outside air. Air should not exit floor,defroster or window defogger outlets.
3. Select heater (floor) mode. Most air should exit floor outlets, with remaining air exiting defroster and window defogger outlets. Air should not exit vent outlets. Air should be about the same temperature as outside air.
4. Select blend (floor-defrost) mode. Equal volume of air should exit defroster and floor outlets, with some air exiting side window defogger outlets.
5. Select defrost mode. Most air should exit defroster outlets, with a low volume of air exiting floor outlets.
6. Select bi-level mode. Move temperature lever to hottest setting. Air should exit vent outlets and its temperature should rapidly increase to about 131°F (55°C) or greater. For more precise heater output temperature check, see HEATER OUTPUT TEMPERATURE CHECK. Defroster nozzle airflow volume should diminish and floor outlet airflow volume may increase slightly.
7. Move temperature lever to coldest setting. Air temperature should decrease to about the same temperature as outside air.
8. Slowly turn blower motor speed control knob toward OFF position, stopping briefly at each intermediate position to check force of airflow exiting instrument panel center outlets to hear blower noise. Airflow and blower noise should decrease noticeably at each intermediate position.

Scheme 1

Scheme 2

Scheme 3

Scheme 4

Scheme 5

TESTING

Note. Equipped with driver-side air bag.

BLOWER MOTOR DOES NOT OPERATE IN ANY SPEED

1. Turn ignition switch to RUN position. Turn mode selector to VENT position. Leave blower switch connector attached. Connect test light between ground and Light Green wire terminal of blower switch connector (backprobe terminal).
2. If test light comes on, go to next step. If test light does not come on, connect test light between ground and Brown wire terminal of mode selector switch connector. If test light does not come on, repair open Brown wire. If test light comes on, check for open Light Green wire. If Light Green wire is okay, replace mode selector switch.
3. Turn ignition switch to RUN position. Turn blower switch to low position. Connect test light between ground and Yellow wire terminal of blower switch connector. If test light comes on, go to next step. If test light does not come on, check for poor connection at Yellow and Light Green wire terminals of blower switch connector. If connections are okay, replace blower switch.
4. Disconnect high blower relay connector (relay is located to right of accelerator pedal, on heater air duct). Connect a fused jumper wire between Dark Blue and Purple wire terminals of high blower relay connector. Turn ignition switch to RUN position. Turn blower switch to low position. Turn mode selector to VENT position.
5. If blower motor does not run, go to next step. If blower motor runs, check for poor connection at high blower relay connector terminals. If connections are okay, replace high blower relay.
6. Leave fused jumper wire connected. Disconnect blower motor connector. Connect test light between Purple and Black wire terminals of blower motor connector. If test light does not come on, go to next step. If test light comes on, check for poor connection at blower motor connector. If connection is okay, replace blower motor.
7. Leave fused jumper wire connected. Connect test light between ground and Purple wire terminal of blower motor connector. If test light comes on, repair open Black wire. If test light does not come on, repair open Purple wire.

BLOWER MOTOR OPERATES IN ALL SPEEDS EXCEPT HIGH

1. Disconnect high blower relay connector (relay is located to right of accelerator pedal, on heater duct). Connect test light between ground and Red wire terminal of high blower relay connector. If test light does not come on, repair open Red wire.
2. If test light comes on, connect test light between Red and Black wire terminals of high blower relay connector. If test light does not come on, repair open Black wire. If test light comes on, turn ignition switch to RUN position.
3. Turn mode selector switch to VENT position. Turn blower switch to high position. Connect test light between ground and Orange wire terminal of high blower relay connector. If test light comes on, replace high blower relay. If test light does not come on, check for open Orange wire. If Orange wire is okay, replace blower switch.

BLOWER MOTOR OPERATES ONLY IN HIGH

1. Turn ignition switch to RUN position. Turn mode selector switch to VENT position. Turn blower switch to low position. Leave blower resistor connector attached. Connect test light between ground and Yellow wire terminal of blower resistor connector (backprobe terminal).
2. If test light comes on, go to next step. If test light does not come on, check for poor connection at blower switch connector. If connection is okay, replace blower switch.
3. Connect test light between ground and Dark Blue wire terminal of blower resistor connector. If test light comes on, go to next step. If test light does not come on, check for poor connection at blower resistor connector. If connection is okay, replace blower resistor.
4. Connect test light between ground and Dark Blue wire terminal of high blower relay connector. If test light does not come on, repair open Dark Blue wire. If test light comes on, check for poor connection at high blower relay connector. If connection is okay, replace high blower relay.

BLOWER MOTOR OPERATES IN HIGH WITH IGNITION SWITCH IN OFF POSITION

Disconnect high blower relay. If blower motor stops, replace high blower relay. If blower motor continues to run, repair short to battery voltage in Purple wire from high blower relay to blower motor.

ONE BLOWER SPEED INOPERATIVE EXCEPT HIGH

1. Disconnect blower resistor connector. Turn ignition switch to RUN position. Turn blower switch to inoperative position. Connect test light between ground and appropriate terminal of blower resistor connector: Low - Yellow wire terminal. Medium-Low - Tan wire terminal. Medium-High - Light Blue wire terminal.
2. If test light does not come on, go to next step. If test light comes on, check for poor connection at blower resistor connector. If connections are okay, replace blower resistor.
3. Connect test light between ground and appropriate terminal of blower switch connector (backprobe terminal): Low - Yellow wire terminal. Medium-Low - Tan wire terminal. Medium-High - Light Blue wire terminal.
4. If test light comes on, repair appropriate wire between blower switch and blower resistor. If test light does not come on, check for poor connection at blower switch connector. If connection is okay, replace blower switch.

REMOVAL & INSTALLATION

Note. Equipped with driver-side air bag.

Disconnect negative battery cable. On Firebird, remove trim plate from around heater control panel. On Camaro, remove upper instrument panel cover and cluster trim plate. On all models, remove heater control panel screws. Pull heater control panel out and disconnect cable, vacuum harness and electrical connectors. Remove heater control panel. To install, reverse removal procedure.

Scheme 6

HEATER CORE

Note. Equipped with driver-side air bag.

Disconnect negative battery cable. Disable air bag system. See the AIR BAG RESTRAINT SYSTEM article in the ACCESSORIES/SAFETY EQUIPMENT section. Drain cooling system. Disconnect heater hoses. Plug hoses and heater core tubes. Squeeze sides of instrument panel compartment to fully open it for access to heater core. Remove heater core cover screws and cover. Remove heater core bolts and heater core. To install, reverse removal procedure. Fill cooling system.

Lock ignition switch in OFF position by removing key. Remove right instrument panel sound insulator assembly and side trim panel. Disconnect blower motor connector. Remove blower motor screws and blower motor. To install, reverse removal procedure.