Procedures
Cabin Heater - Installation
ℹ NOTE
LHD model shown. RHD model similar.ℹ NOTE
PTC heater shown removed from distribution housing for clarity.ℹ NOTE
If the retaining tabs on the actuator mounting bracket become broken during service, the alignment pins on the bracket bosses can be removed and screws can be used to retain the actuator to the bracket. Once the alignment pins are removed, pre-made holes can be found the center of the bosses, exactly where the pins were. This assures correct actuator alignment to the bracket. Use care not to overtighten the screws and damage the bosses.
- Carefully install the positive temperature coefficient (PTC) heater unit (2) into the driver side of the air distribution housing (3). Make sure to position the two locator tabs on the end of the heater unit into the molded locator indentations on the right side of the air distribution housing.
- Install the two screws (1) that secure the PTC heater unit to the air distribution housing. Tighten the screws to 1.2 Nm (10 in. lbs.).
- Connect the wire harness connector (1) to the PTC heater unit (3) while pushing inward on the connector lock (2). Make sure the wire harness connector and lock are fully engaged.
- Install the driver side front floor duct (7) onto the driver side of the air distribution housing (4) and install the retaining screw (8). Tighten the screw to 1.2 Nm (10 in lbs.).
- Position the actuator mounting bracket (5) onto the air distribution housing and install the three retaining screws (1). Tighten the screws to 1.2 Nm (10 in lbs.).
- Position the mode door actuator (2) and the blend door actuator (6) onto the actuator mounting bracket. If necessary, rotate the actuator slightly to align the splines on the actuator output shaft with those on the door linkage.
- Engage the retaining tabs (3) that secure the mode and blend door actuators to the actuator mounting bracket. Make sure the retaining tabs are fully engaged.
- Connect the wire harness connector to the mode and blend door actuators.
- If equipped, install the silencer below the driver side of the instrument panel.
- Reconnect the negative battery cable.
Cabin Heater - Removal
⚠ WARNING
Disable the airbag system before attempting any steering wheel, steering column or instrument panel component diagnosis or service. Disconnect and isolate the negative battery (ground) cable and wait two minutes for the airbag system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the airbag system. Failure to follow these instructions may result in accidental airbag deployment and possible serious or fatal injury.ℹ NOTE
LHD model shown in illustrations. RHD model similar.ℹ NOTE
PTC heater shown removed from distribution housing for clarity.ℹ NOTE
To disconnect the wire harness connector from the PTC heater, disengage the connector lock while pulling the connector away from the heater unit.
- Disconnect and isolate the negative battery cable.
- If equipped, remove the silencer from below the driver side of the instrument panel.
- Disconnect the wire harness connector from the mode door actuator (2) and the blend door actuator (6) located on the driver side of the air distribution housing Mode Door Actuator - Removal.
- Carefully disengage the retaining tabs (3) that secure the mode door actuator and the blend door actuator to the actuator mounting bracket (5) and remove the actuators.
- Remove the three screws (1) that secure the actuator mounting bracket to the air distribution housing and remove the bracket.
- Remove the screw (8) that secures the driver side front floor duct (7) to the air distribution housing and remove the duct
- Disengage the wire connector lock (2) that secures the wire harness connector (1) to the positive temperature coefficient (PTC) heater unit (3) and disconnect the connector from the heater.
- Remove the two screws (1) that secure the PTC heater unit (2) to the air distribution housing (3).
- Carefully pull the PTC heater unit straight out of the air distribution housing.
Auxiliary Cabin Heater: Testing and Inspection
⚠ WARNING
Disable the airbag system before attempting any steering wheel, steering column or instrument panel component diagnosis or service. Disconnect and isolate the negative battery (ground) cable, then wait two minutes for the airbag system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the airbag system. Failure to follow these instructions may result in accidental airbag deployment and possible serious or fatal injury.ℹ NOTE
See Wiring Information for circuit descriptions and diagrams. Wiring Information includes wiring diagrams, proper wire and connector repair procedures, further details on wire harness routing and retention as well as pin-out and location views for the various wire harness connectors, splices and grounds.- Disconnect and isolate the negative battery cable.
- Disconnect the wire harness connector from the PTC heater unit Cabin Heater - Removal.
- Using an ohmmeter, check for continuity between all of the PTC heater unit terminals. In each case there should be continuity. If OK, repair the wire harness circuits between the PTC heater unit and the TIPM. If NOT OK, replace the PTC heater unit.
Cabin Heater - Description
ℹ NOTE
LHD model shown. RHD model similar.
DESCRIPTION An electric positive temperature coefficient (PTC) heater unit (1) is used on vehicles when equipped with the 2.8L diesel engine. The PTC heater unit aids in passenger compartment heating by compensating for the lower engine coolant temperatures produced by the diesel engine. The PTC heater unit is mounted in the HVAC air distribution housing, downstream of the heater core and is controlled by the diesel engine control module (ECM) and the totally integrated power module (TIPM) through two relays in diesel accessory fuse/relay block located below the left front fender. The PTC heater consists of a molded plastic mounting plate (2) with an integral wire connector receptacle (3). Concealed behind the mounting plate are four heating elements with fins (4) that transfer the heat produced by the PTC heater to the conditioned air flowing within the air distribution housing. A positioning tab (5) is molded onto the end of the heater unit to help support the heater unit inside the air distribution housing. The PTC heater unit is connected to the vehicle electrical system through the instrument panel wire harness. The PTC heater unit is accessed for service from underneath the instrument panel.
Factory service manual
From the 2008 KK factory manual — descriptions, specs, torque & procedures for this part.
HEATER UNIT
NOTE: LHD model shown in illustration. RHD model similar.
An electric positive temperature coefficient (PTC) heater unit (1) is used on vehicles when equipped with the 2.8L diesel engine. The PTC heater unit aids in passenger compartment heating by compensating for the lower engine coolant temperatures produced by the diesel engine. The PTC heater unit is mounted in the HVAC air distribution housing, downstream of the heater core and is controlled by the diesel engine control module (ECM) and the totally integrated power module (TIPM) through two relays in diesel accessory fuse/relay block located below the left front fender.
The PTC heater consists of a molded plastic mounting plate (2) with an integral wire connector receptacle (3). Concealed behind the mounting plate are four heating elements with fins (4) that transfer the heat produced by the PTC heater to the conditioned air flowing within the air distribution housing. A positioning tab (5) is molded onto the end of the heater unit to help support the heater unit inside the air distribution housing. The
PTC heater unit is connected to the vehicle electrical system through the instrument panel wire harness.
The PTC heater unit is accessed for service from underneath the instrument panel.
HEATER UNIT
The positive temperature coefficient (PTC) heater unit dissipates 1 kW of electrical power through 4 heating bars. The totally integrated power module (TIPM) operates the two relays for the PTC heater unit. The PTC heater unit is split into two "banks". Each bank is driven separately based on alternator load. This allows for lower in-rush current and optimum battery charging. After a bank has been turned on, another bank can only be turned on 10 seconds after the previous. On average, the PTC banks are not switched more than 25 times for each vehicle start. Electrical power output is between 900-1050 W.
The control system for the PTC heater unit is diagnosed using a scan tool. Prior to replacing a PTC heater unit, check for any diagnostic trouble codes (DTCs) related to the ECM, TIPM and heating-A/C system (refer to HEATING & AIR CONDITIONING - ELECTRICAL DIAGNOSTICS article for more information).
The PTC heater unit cannot be adjusted or repaired and, if faulty or damaged it must be replaced.
HEATER UNIT
WARNING: Disable the airbag system before attempting any steering wheel, steering column, or instrument panel component diagnosis or service. Disconnect and isolate the negative battery (ground) cable, then wait two minutes for the airbag system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the airbag system. Failure to take the proper precautions could result in accidental airbag deployment and possible serious or fatal injury.
NOTE: For circuit descriptions and diagrams, refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, further details on wire harness routing and retention, as well as pin-out and location views for the various wire harness connectors, splices and grounds.
Prior to replacing the positive temperature coefficient (PTC) heater unit, check for any diagnostic trouble codes (DTCs) related to the engine control module (ECM), totally integrated power module (TIPM) and the heating- A/C system and repair as necessary (refer to HEATING & AIR CONDITIONING - ELECTRICAL DIAGNOSTICS article for more information).
1. Disconnect and isolate the negative battery cable. 2. Disconnect the wire harness connector from the PTC heater unit. See REMOVAL. 3. Using an ohmmeter, check for continuity between all of the PTC heater unit terminals. In each case there
should be continuity. If OK, repair the wire harness circuits between the PTC heater unit and the TIPM. If NOT OK, replace the PTC heater unit.
HEATER UNIT
WARNING: Disable the airbag system before attempting any steering wheel, steering column, or instrument panel component diagnosis or service. Disconnect and isolate the negative battery (ground) cable, then wait two minutes for the airbag system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the airbag system. Failure to take the proper precautions could result in accidental airbag deployment and possible personal injury or death.
NOTE: LHD model shown in illustrations. RHD model similar.
1. Disconnect and isolate the negative battery cable. 2. If equipped, remove the silencer from below the driver side of the instrument panel. Refer to
Removal
3
Disconnect the wire harness connector from the mode door actuator (2) and the blend door actuator (6)
located on the driver side of the air distribution housing. See REMOVAL.
4
Carefully disengage the retaining tabs (3) that secure the mode door actuator and the blend door actuator
to the actuator mounting bracket (5) and remove the actuators.
5
Remove the three screws (1) that secure the actuator mounting bracket to the air distribution housing and
remove the bracket.
6
Remove the screw (8) that secures the driver side front floor duct (7) to the air distribution housing and
remove the duct
NOTE
PTC heater shown in illustration removed from distribution housing for clarity.NOTE
To disconnect the wire harness connector from the PTC heater, disengage the connector lock while pulling the connector away from the heater unit.7
Disengage the wire connector lock (2) that secures the wire harness connector (1) to the positive
temperature coefficient (PTC) heater unit (3) and disconnect the connector from the heater.
8
Remove the two screws (1) that secure the PTC heater unit (2) to the air distribution housing (3).
9
Carefully pull the PTC heater unit straight out of the air distribution housing.
HEATER UNIT
NOTE: LHD model shown in illustration. RHD model similar.
1. Carefully install the positive temperature coefficient (PTC) heater unit (2) into the driver side of the air distribution housing (3). Make sure to position the two locator tabs on the end of the heater unit into the molded locator indentations on the right side of the air distribution housing. 2. Install the two screws (1) that secure the PTC heater unit to the air distribution housing. Tighten the screws to 1.2 N.m (10 in. lbs.).
NOTE: PTC heater shown in illustration removed from distribution housing for clarity.
3. Connect the wire harness connector (1) to the PTC heater unit (3) while pushing inward on the connector lock (2). Make sure the wire harness connector and lock are fully engaged.
4. Install the driver side front floor duct (7) onto the driver side of the air distribution housing (4) and install the retaining screw (8). Tighten the screw to 1.2 N.m (10 in lbs.). 5. Position the actuator mounting bracket (5) onto the air distribution housing and install the three retaining screws (1). Tighten the screws to 1.2 N.m (10 in lbs.). 6. Position the mode door actuator (2) and the blend door actuator (6) onto the actuator mounting bracket. If necessary, rotate the actuator slightly to align the splines on the actuator output shaft with those on the door linkage.
NOTE: If the retaining tabs on the actuator mounting bracket become broken during service, the alignment pins on the bracket bosses can be removed and screws can be used to retain the actuator to the bracket. Once the alignment pins are removed, pre-made holes can be found the center of the bosses, exactly where the pins were. This assures correct actuator alignment to the bracket. Use care not to overtighten the screws and damage the bosses.
7. Engage the retaining tabs (3) that secure the mode and blend door actuators to the actuator mounting bracket. Make sure the retaining tabs are fully engaged. 8. Connect the wire harness connector to the mode and blend door actuators. 9. If equipped, install the silencer below the driver side of the instrument panel. Refer to
Installation
10
Reconnect the negative battery cable.
RELAY-HEATER UNIT
HEATER UNIT
NOTE: LHD model shown in illustration. RHD model similar.
An electric positive temperature coefficient (PTC) heater unit (1) is used on vehicles when equipped with the 2.8L diesel engine. The PTC heater unit aids in passenger compartment heating by compensating for the lower engine coolant temperatures produced by the diesel engine. The PTC heater unit is mounted in the HVAC air distribution housing, downstream of the heater core and is controlled by the diesel engine control module (ECM) and the totally integrated power module (TIPM) through two relays in diesel accessory fuse/relay block located below the left front fender.
The PTC heater consists of a molded plastic mounting plate (2) with an integral wire connector receptacle (3). Concealed behind the mounting plate are four heating elements with fins (4) that transfer the heat produced by the PTC heater to the conditioned air flowing within the air distribution housing. A positioning tab (5) is molded onto the end of the heater unit to help support the heater unit inside the air distribution housing. The
PTC heater unit is connected to the vehicle electrical system through the instrument panel wire harness.
The PTC heater unit is accessed for service from underneath the instrument panel.
HEATER UNIT
The positive temperature coefficient (PTC) heater unit dissipates 1 kW of electrical power through 4 heating bars. The totally integrated power module (TIPM) operates the two relays for the PTC heater unit. The PTC heater unit is split into two "banks". Each bank is driven separately based on alternator load. This allows for lower in-rush current and optimum battery charging. After a bank has been turned on, another bank can only be turned on 10 seconds after the previous. On average, the PTC banks are not switched more than 25 times for each vehicle start. Electrical power output is between 900-1050 W.
The control system for the PTC heater unit is diagnosed using a scan tool. Prior to replacing a PTC heater unit, check for any diagnostic trouble codes (DTCs) related to the ECM, TIPM and heating-A/C system (refer to HEATING & AIR CONDITIONING - ELECTRICAL DIAGNOSTICS article for more information).
The PTC heater unit cannot be adjusted or repaired and, if faulty or damaged it must be replaced.
HEATER UNIT
WARNING: Disable the airbag system before attempting any steering wheel, steering column, or instrument panel component diagnosis or service. Disconnect and isolate the negative battery (ground) cable, then wait two minutes for the airbag system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the airbag system. Failure to take the proper precautions could result in accidental airbag deployment and possible serious or fatal injury.
NOTE: For circuit descriptions and diagrams, refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, further details on wire harness routing and retention, as well as pin-out and location views for the various wire harness connectors, splices and grounds.
Prior to replacing the positive temperature coefficient (PTC) heater unit, check for any diagnostic trouble codes (DTCs) related to the engine control module (ECM), totally integrated power module (TIPM) and the heating- A/C system and repair as necessary (refer to HEATING & AIR CONDITIONING - ELECTRICAL DIAGNOSTICS article for more information).
1. Disconnect and isolate the negative battery cable. 2. Disconnect the wire harness connector from the PTC heater unit. See REMOVAL. 3. Using an ohmmeter, check for continuity between all of the PTC heater unit terminals. In each case there
should be continuity. If OK, repair the wire harness circuits between the PTC heater unit and the TIPM. If NOT OK, replace the PTC heater unit.
HEATER UNIT
WARNING: Disable the airbag system before attempting any steering wheel, steering column, or instrument panel component diagnosis or service. Disconnect and isolate the negative battery (ground) cable, then wait two minutes for the airbag system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the airbag system. Failure to take the proper precautions could result in accidental airbag deployment and possible personal injury or death.
NOTE: LHD model shown in illustrations. RHD model similar.
1. Disconnect and isolate the negative battery cable. 2. If equipped, remove the silencer from below the driver side of the instrument panel. Refer to
Removal
3
Disconnect the wire harness connector from the mode door actuator (2) and the blend door actuator (6)
located on the driver side of the air distribution housing. See REMOVAL.
4
Carefully disengage the retaining tabs (3) that secure the mode door actuator and the blend door actuator
to the actuator mounting bracket (5) and remove the actuators.
5
Remove the three screws (1) that secure the actuator mounting bracket to the air distribution housing and
remove the bracket.
6
Remove the screw (8) that secures the driver side front floor duct (7) to the air distribution housing and
remove the duct
NOTE
PTC heater shown in illustration removed from distribution housing for clarity.NOTE
To disconnect the wire harness connector from the PTC heater, disengage the connector lock while pulling the connector away from the heater unit.7
Disengage the wire connector lock (2) that secures the wire harness connector (1) to the positive
temperature coefficient (PTC) heater unit (3) and disconnect the connector from the heater.
8
Remove the two screws (1) that secure the PTC heater unit (2) to the air distribution housing (3).
9
Carefully pull the PTC heater unit straight out of the air distribution housing.
HEATER UNIT
NOTE: LHD model shown in illustration. RHD model similar.
1. Carefully install the positive temperature coefficient (PTC) heater unit (2) into the driver side of the air distribution housing (3). Make sure to position the two locator tabs on the end of the heater unit into the molded locator indentations on the right side of the air distribution housing. 2. Install the two screws (1) that secure the PTC heater unit to the air distribution housing. Tighten the screws to 1.2 N.m (10 in. lbs.).
NOTE: PTC heater shown in illustration removed from distribution housing for clarity.
3. Connect the wire harness connector (1) to the PTC heater unit (3) while pushing inward on the connector lock (2). Make sure the wire harness connector and lock are fully engaged.
4. Install the driver side front floor duct (7) onto the driver side of the air distribution housing (4) and install the retaining screw (8). Tighten the screw to 1.2 N.m (10 in lbs.). 5. Position the actuator mounting bracket (5) onto the air distribution housing and install the three retaining screws (1). Tighten the screws to 1.2 N.m (10 in lbs.). 6. Position the mode door actuator (2) and the blend door actuator (6) onto the actuator mounting bracket. If necessary, rotate the actuator slightly to align the splines on the actuator output shaft with those on the door linkage.
NOTE: If the retaining tabs on the actuator mounting bracket become broken during service, the alignment pins on the bracket bosses can be removed and screws can be used to retain the actuator to the bracket. Once the alignment pins are removed, pre-made holes can be found the center of the bosses, exactly where the pins were. This assures correct actuator alignment to the bracket. Use care not to overtighten the screws and damage the bosses.
7. Engage the retaining tabs (3) that secure the mode and blend door actuators to the actuator mounting bracket. Make sure the retaining tabs are fully engaged. 8. Connect the wire harness connector to the mode and blend door actuators. 9. If equipped, install the silencer below the driver side of the instrument panel. Refer to
Installation
10
Reconnect the negative battery cable.
RELAY-HEATER UNIT
