Heater System: Other Dodge Ram Van B2500

Blower Motor Switch

Fan speed is controlled with a rotary blower motor 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 air flow. There are 5 different modes of operation: panel, floor/panel, floor, floor/defrost, and defrost.

Temperature Control Knob

Rotary control knob determines discharge air temperature by positioning blend/air door. On Dakota and Durango, temperature blend-air door is cable operated. On Ram Pickup and Ram Van/Wagon, temperature blend-air door is electrically operated. When a hot temperature is selected, all air flows through heater core.

Dakota & Durango

1. Ensure temperature control cable housing and core are connected at both heater control panel and heater assembly. Ensure heater control panel is properly installed.
2. Rotate temperature control knob so that knob pointer is at 12 o'clock position. Pull temperature control knob straight out from heater control panel until perimeter of knob (not knob pointer) protrudes about.25" (6 mm) from face of heater control panel.
3. Rotate temperature control knob clockwise so that knob pointer is at one o'clock position. Push in on knob slightly and continue rotating knob to its full clockwise stop. Place knob pointer at a position about.32" (8 mm) beyond end of Red stripe. Release knob. If knob is pointing at about.32" (8 mm) beyond end of Red stripe, go to next step. If knob is not pointing at about.32" (8 mm) beyond end of Red stripe, go back to step 2 and repeat adjustment procedure.
4. Rotate temperature control knob counterclockwise so that knob pointer is at 12 o'clock position. Push temperature control knob straight into heater control panel until perimeter of knob (not knob pointer) is flush with base of heater control panel.
5. Rotate temperature control knob to its full clockwise stop. Release knob. Knob pointer should be aimed at end of Red stripe. If knob is pointed at end of Red stripe, go to next step. If knob is not pointed at end of Red stripe, go back to step 2 and repeat adjustment procedure.
6. Rotate temperature control knob to its full counterclockwise stop. Release knob. If knob springs back, self-adjuster clip securing temperature control cable to blend-air door lever is improperly installed. See «TEMPERATURE CONTROL CABLE»(ref-196-S04003520432000030800000) under REMOVAL & INSTALLATION. If knob does not springs back, temperature control cable adjustment is complete.

HEATER PERFORMANCE

Check cooling system. Check serpentine drive belt tension. Check radiator and radiator fan operation. Ensure that accessory vacuum supply line is connected at power brake booster (Dakota) or engine vacuum source (except Dakota).

BLOWER MOTOR RELAYS

1. Blower motor relay is located in Power Distribution Center (PDC). On Ram Van/Wagon, high speed blower motor relay is located in engine compartment (on side of heater assembly). On all models, disconnect negative battery cable. Remove blower motor relay. Using an ohmmeter, check for continuity between terminals No. 87A and 30 of relay. (Scheme 13) If continuity does not exist, replace relay. If continuity exists, go to next step.
2. Using an ohmmeter, check for continuity between terminals No. 30 and 87 of relay. If continuity exists, replace relay. If continuity does not exist, go to next step.
3. 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.
4. Using jumper wires, connect battery voltage to terminal No. 86 and ground terminal No. 85. (Scheme 13) 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 13

BLOWER MOTOR RESISTOR

1. Disconnect negative battery cable. Disconnect blower motor resistor harness connector. Using an ohmmeter, check for continuity between all blower motor resistor terminals. If continuity exists between all terminals, go to next step. If continuity does not exist between all terminals, replace faulty blower motor resistor.
2. Check for open or short in circuits between blower motor resistor and heater control panel. Also check for open or short in wire between blower motor resistor and blower motor.

Dakota, Durango & Ram Pickup

1. Using a voltmeter, check for battery voltage at underhood power distribution center fuse No. 5 (40-amp) on Dakota and Durango; fuse No. 12 (40-amp) on Ram Pickup. If battery voltage exists, go to next step. If battery voltage does not exist, check for open in Red wire between battery and underhood power distribution center. If Red wire is okay, replace underhood power distribution center.
2. Disconnect negative battery cable. Remove heater control panel. See «HEATER CONTROL PANEL»(ref-196-S30366798952000030800000) under REMOVAL & INSTALLATION. Disconnect heater control panel harness connector. Using an ohmmeter, check for continuity between heater control panel harness connector terminal No. 7 (Black wire on Dakota and Durango; Black/Orange on Ram Pickup) and ground. If continuity exists, go to step 4.
3. If continuity does not exist, repair open in Black wire or Black/Orange wire between heater control panel harness connector terminal No. 7 and ground connector located at lower right corner of instrument panel (Dakota and Durango) or behind center of instrument panel (Ram Pickup).
4. Place heater mode control knob to any position except OFF. Using an ohmmeter, check for continuity between heater control panel connector terminal No. 7 and terminals No. 3, 4, 5 and 6 while rotating blower motor switch. (Scheme 14)
5. If continuity does not exist at any terminal, replace faulty heater control panel. If continuity exists as specified, check for open in circuits between heater control panel and blower motor resistor. Also check for an open in circuit between heater control panel and blower motor.

Scheme 14

Ram Van/Wagon

1. Disconnect negative battery cable. Remove heater control panel. See «HEATER CONTROL PANEL»(ref-196-S30366798952000030800000) under REMOVAL & INSTALLATION. Disconnect heater control panel harness connector. Using an ohmmeter, check for continuity between heater control panel C3 harness connector terminal "C" (Black wire) and ground. (Scheme 16) Go to next step.
2. If continuity exists, go to next step. If continuity does not exist, repair open in Black wire between heater control panel and ground connector located at lower right of steering column.
3. Place heater mode control knob to any position except OFF. Using an ohmmeter, check for continuity between heater control panel C3 connector terminals "B" (Violet wire) and "C" (Black wire). If continuity exists, go to next step. If continuity does not exist, replace faulty heater control panel.
4. Using an ohmmeter, check for continuity between heater control panel C3 connector terminal "B" (Violet wire) and C1 connector terminal "E" (Violet wire). (Scheme 15) If continuity exists, go to next step. If continuity does not exist, repair open in Violet wire between heater control panel C3 and C1 connectors.
5. Using an ohmmeter, check for continuity between heater control panel C1 connector terminal "E" and terminals "B", "C" and "D" while rotating blower motor switch. (Scheme 15)
6. If continuity does not exist at any terminal, replace faulty heater control panel. If continuity exists as specified, check for open in circuits between heater control panel and blower motor resistor. Also check for an open in circuit between heater control panel connector and blower motor relay.

Scheme 15

Scheme 16

HEATER CONTROL PANEL

1. Connect a vacuum gauge in line with Black heater vacuum supply hose (located at tee near power brake booster, in engine compartment). Position gauge so it can be viewed from passenger compartment.
2. Start engine. While observing vacuum gauge, rotate mode control knob to each mode position (one position at a time). Pause after each selection. Vacuum gauge should drop then return to 8 in. Hg shortly after each selection is made. If vacuum gauge reading is as specified, go to next step. If gauge reading is not as specified, check for vacuum leak in vacuum lines or heater control panel.
3. Move temperature control knob quickly to full hot and full cold positions. A distinct sound of blend-air door hitting its stops should be heard. No spring-back of knob should exist.
4. If temperature control knob operates as specified, temperature control system is okay. If temperature control knob does not operate as specified, check condition, routing, installation and adjustment of temperature control cable. See «TEMPERATURE CONTROL CABLE»(ref-196-S01017033242000030800000) under ADJUSTMENTS.

HEATER OUTPUT

1. Start engine. Allow engine to reach normal operating temperature. With engine at idle, set controls to maximum heat, floor and high blower positions. Using a thermometer, check air temperature coming from floor vents. See «HEATER OUTPUT TEMPERATURE»(ref-196-S16255456352000030800000) table.
2. If floor outlet air temperature is lower than specified, check cooling system and electric cooling fan. See ELECTRIC COOLING FANS - ALL OTHER MODELS article.
3. Check that both return and supply heater hoses are hot. If coolant return hose is much cooler than supply hose, repair coolant obstruction in heater system. Check for air flow obstruction in heater system. Check blend air door for proper operation.

HEATER OUTPUT TEMPERATURE