Heater System Dodge Pickup R2500

DESCRIPTION

Ram Pickup uses a blend-air system. Outside air enters heater through cowl opening and passes through a plenum chamber to heater core. A temperature control door in heater housing either directs incoming air through or around heater core.

Once past heater core, heated air and unheated air are mixed, producing air at desired temperature. Heater discharge is then directed through dash panel to air distribution duct in passenger compartment.

HEATER CONTROL PANEL

The panel contains a 4-position fan switch, a rotary temperature control switch and a rotary air direction control switch.

Fan Switch

Fan speed is controlled with a rotary switch. There are 4 different fan speed settings: one low speed, 2 medium speeds and one high speed.

Mode Control Knob

A rotary mode switch is used to control airflow. There are 5 different modes of operation: panel, floor/panel, floor, floor/defrost and defrost. Different modes of operation are identified by symbols on control panel. This switch controls vacuum signals to move different air outlet doors.

Temperature Control Knob

Rotary control knob determines discharge air temperature by manually positioning temperature blend/air door. Temperature blend/air door is cable operated. When a hot temperature is selected, all air flows through heater core.

TESTING

BLOWER MOTOR RELAY

1. Relay is located on brake light support bracket.
2. Remove relay, using a test light connected to ground, check for battery voltage at cavity No. 30 of PDC. (Scheme 1) If battery voltage is not present, check fuse No. 7 (25-amp) of passenger compartment fuse box. If battery voltage exists, go to next step.
3. Using an ohmmeter, check for continuity between terminals No. 87A and 30 of relay. (Scheme 1) If continuity does not exist, replace relay. Check that continuity does not exist between terminals No. 30 and 87. If continuity exists, replace relay. If continuity does not exist, go to next step.
4. Measure resistance between terminals No. 85 and 86 of relay. Reading should be 70-80 ohms. If reading is not as specified, replace relay. If reading is as specified, go to next step.
5. Using jumper wires, connect battery voltage to terminal No. 86 and ground terminal No. 85. (Scheme 1) Check that continuity exists between terminals No. 30 and 87. Check that continuity does not exist between terminals No. 87A and 30. If continuity is not as specified, replace blower motor relay. If continuity is as specified, relay is okay.

Scheme 1

REMOVAL & INSTALLATION

1. Blower motor is located under glove box and can be removed from passenger compartment. (Scheme 2) Disconnect negative battery cable. Disconnect blower motor cooling tube. Remove blower motor electrical connector from retainer.
2. Disconnect electrical connector. Remove blower motor and wheel assembly mounting screws. Remove blower motor and wheel assembly. Remove blower motor wheel retainer clip. Pull blower motor wheel off blower motor shaft. To install, reverse removal procedure.

Scheme 2

Blower motor resistor is located under glove box, attached to blower motor housing. (Scheme 2) Disconnect negative battery cable. Remove blower motor resistor connector. Remove resistor retaining screws. Remove blower motor resistor. To install, reverse removal procedure.

1. Disconnect negative battery cable. Remove 2 screws from cup holder and remove cup holder assembly. Remove 2 screws from ashtray and remove ashtray. Carefully pry bezel away from instrument panel to disengage clips. Unplug connectors from cigarette lighter and auxiliary power outlet.
2. Remove 4 screws attaching heater control panel. Pull control panel rearward. Disconnect wiring harness and vacuum connectors. Push inward on Red cable connector to release connector. Remove cable end from heater control panel. Remove heater control panel. To install, reverse removal procedure.

1. Disconnect negative battery cable. Drain cooling system. In engine compartment, remove coolant hoses from heater core tubes. Plug all openings. Remove coolant overflow bottle. Remove Powertrain Control Module (PCM) and position aside. DO NOT disconnect 60-pin connector from PCM.
2. Remove attaching nuts from studs on engine compartment side of dash panel. Remove instrument panel. See «INSTRUMENT PANEL»(/dodge/pickup-r2500/1997-1998/remont/heater/#heater-system) . Remove defrost duct. Disconnect electrical connectors. Remove attaching nuts from studs in passenger compartment side of dash panel. Remove heater unit from vehicle. To install, reverse removal procedure.

1. Disable air bag system. See the AIR BAG RESTRAINT SYSTEM article. Disconnect negative battery cable. Drain cooling system. Remove left and right kick panel trim. Remove 5 screws and knee blocker/steering column cover. Remove hood release and parking brake release handle screws from lower instrument panel support. Remove 6 screws and instrument panel support. Disconnect air bag connector at lower left corner of instrument panel.
2. Pull PRNDL cable and twist to remove from position arm. Push tab on bottom of cable retainer upward, then squeeze sides to remove retainer from column. Remove tilt lever (tilt column only). Remove both upper and lower shrouds from column. Remove lower fixed column shroud. Loosen multi-function switch connector screw. Screw will remain in connector.
3. Remove remaining steering column electrical connectors. Remove air bag wiring harness from steering column wiring trough. Remove wiring trough from steering column. Remove 3 toe plate nuts and washers.
4. Remove 2 nuts and washers attaching steering column bracket to instrument panel steering column support bracket. Allow column to lower and rest on seat. Remove 2 screws from bottom of Air Bag Control Module (ACM) cover. Remove 4 screws holding ACM to transmission tunnel. Disconnect wiring at ACM.
5. Disconnect instrument panel left side wiring connectors. Remove screw holding brake release to bottom of instrument panel. Disconnect instrument panel right side wiring connectors, which includes 2 connectors attached to heater housing, courtesy light connector, antenna cable and 2 body connectors. Disconnect vacuum harness for heater system.
6. Remove 5 screws holding instrument panel to dash. Loosen lower instrument panel pivot bolts. Roll instrument panel downward. Using a screwdriver, push through plastic flashing to release locking tab on heater control cable. Pull cable from top of heater core housing. Remove instrument panel from vehicle.
7. To install, reverse removal procedure. Ensure all wiring and hoses are clear and not pinched. Tighten bolts and nuts to specification. See «TORQUE SPECIFICATIONS»(/dodge/pickup-r2500/1997-1998/remont/heater/#heater-system__torque-specifications) . Enable air bag system. See the AIR BAG RESTRAINT SYSTEM article.

Lower steering column and pivot instrument panel downward. See INSTRUMENT PANEL . Disconnect cable from top of heater housing. Remove heater control panel. See CONTROL PANEL . Release control cable housing retainer flag and remove cable. Disconnect cable core from heater control panel. To install, reverse removal procedure.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

Scheme 3

See also:
• INSTRUMENT PANEL
• TORQUE SPECIFICATIONS