Heater System Dodge Ram Wagon B3500

DESCRIPTION

All models use 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.

Vans may have optional auxiliary rear heater unit. Rear heater unit consists of a heater core and 3-speed blower motor enclosed in a housing. Rear heater unit is mounted on floor, behind driver's seat. Rear heater unit recirculates air inside vehicle.

Auxiliary rear heater unit's coolant flow control valve is engaged after instrument panel's temperature control lever is moved past its first quarter of travel. Auxiliary rear heater blower speeds are controlled by a separate 4-position toggle switch mounted on instrument panel, below heater controls. (Scheme 5)

HEATER CONTROL PANEL

Control panel contains a COOL-to-WARM temperature control lever; an OFF, HEAT and defrost mode lever; and a 4-position fan switch.

Fan Switch

Four-position switch allows operation of fan at 3 different speeds. Lever-type switch has OFF, low, medium and HI (high) positions.

Mode Control Lever

Mode lever positions mode door in air distribution duct. Door directs air to heater or defroster ducts.

Temperature Control Lever

Control lever operates blend-air door. When in far left position, air by-passes heater core, producing cool air for ventilation. As lever is moved to right, blend-air door directs air through heater core to provide a mixture of unheated and heated air. In far right position, all air is directed through heater core, providing maximum heat.

CONTROL CABLES

Note. See MODE CONTROL CABLE and TEMPERATURE CONTROL CABLE under REMOVAL & INSTALLATION.

REMOVAL & INSTALLATION

Remove auxiliary heater assembly. See AUXILIARY HEATER ASSEMBLY & HEATER CORE . Remove blower motor screws. Remove blower motor from inside heater assembly. To install, reverse removal procedure.

Removal

1. Disconnect negative battery cable. Drain coolant from radiator. From under vehicle, disconnect auxiliary heater inlet and outlet hoses from heater core tubes.
2. Remove auxiliary housing lower cover screws. Remove heater core tube seal and cover plate. Remove screws from heater core support bracket and remove support bracket. Remove heater core from housing. To install, reverse removal procedure. Check system operation.

1. Remove top half of radiator shroud. At right side of engine compartment, disconnect blower motor wiring connector and motor cooling tube.
2. Remove nuts and washers from blower motor backing plate to heater housing studs. (Scheme 1) Remove blower motor assembly.
3. Inside blower wheel, remove spring clip fastening blower wheel to blower motor. Inspect backing plate seal for breaks and adhesion. To install, reverse removal procedure.

Scheme 1

1. Disconnect negative battery cable. Remove 2 heater control panel bezel screws. Remove bezel enough to disconnect switches and cigarette lighter wiring. Remove heater control panel screws.
2. Pull control panel outward enough to disconnect electrical connector(s) and control cables. Remove heater control panel. To install, reverse removal procedure. Adjust control cables as required. See «ADJUSTMENTS»(/dodge/ram-wagon-b3500/1991-2000/remont/heater/#heater-system) .

1. Disconnect negative battery cable. Drain engine cooling system. In engine compartment, remove heater hoses from heater core tubes.
2. Disconnect temperature control cable from heater housing top cover and from blend-air door crank. Disconnect right vent door cable. Disconnect blower motor wiring connector. (Scheme 2)
3. Remove 2 screws (top and bottom) fastening heater assembly to side cowl. Remove 2 nuts, behind glove box, from heater assembly to firewall. Remove 2 nuts, on outside of heater housing, from heater assembly to firewall.
4. Lift heater assembly out of engine compartment. Remove heater housing top cover. Remove 2 heater core screws from bottom of heater housing. Remove heater core.

Installation

To install, reverse removal procedure. Ensure heater housing top cover seal, firewall and side cowl seals are in good condition. Adjust both cables as required. See ADJUSTMENTS .

Scheme 2

1. Remove engine cover. Depress tab on flag and pull control cable out of receiver on distribution duct. (Scheme 3)and (Scheme 5). Remove heater control panel. See «CONTROL PANEL»(/dodge/ram-wagon-b3500/1991-2000/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Depress tab on flag and pull mode control cable out of receiver on heater control. Remove cable.
2. To remove self-adjusting clip, hold core wire firmly at both ends of clip. Using a tube or rod, pry clip off cable core wire. (Scheme 4)

Scheme 3

1. To install self-adjusting clip, position clip onto cable core wire about 2" from wire loop end. Using a tube or rod, pry clip into locked position. (Scheme 4)
2. On heater control panel, slide cable core wire loop onto mode control lever pin, and snap flag into receiver. Install heater control panel. Place mode lever in far left position. Partially insert flag in receiver on distribution duct.
3. Slide self-adjusting clip over crankpin and snap flag into place. Adjust cable by moving control lever to far right position. Install engine cover.

Scheme 4

Scheme 5

1. In engine compartment, remove temperature control cable from heater assembly and blend-air door crank. (Scheme 2) Using a tube, pry self-adjusting clip off cable core wire. (Scheme 4) Remove glove box and engine cover.
2. Pull cable through firewall into passenger compartment. Depress tab on flag, and pull mode control cable out of receiver on distribution duct. (Scheme 3)and (Scheme 5). Remove heater control panel. See «CONTROL PANEL»(/dodge/ram-wagon-b3500/1991-2000/remont/heater/#heater-system) under REMOVAL & INSTALLATION. Depress tab on flag, and pull temperature control cable out of receiver on heater control panel. Remove cable.

1. To install, properly route cable through vehicle. (Scheme 5) On heater control panel, slide cable core wire loop end onto temperature control lever pin and snap flag into receiver. Install heater control panel. Snap mode control cable flag into receiver on distribution duct. (Scheme 5) Place self-adjusting clip onto crank arm pin.
2. Readjust mode cable by positioning self-adjusting clip on core wire about 2" from loop end of temperature control cable. Using tube or rod, pry clip into locked position. (Scheme 4) Place self-adjusting clip over blend-air door crankpin. Snap cable into retaining clip. (Scheme 2)
3. Locating tape should be next to side of clip farthest from crank arm. Adjust cable by moving temperature control lever to extreme right position. Install engine cover.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

Scheme 6

Scheme 7

Scheme 8

See also:
• AUXILIARY HEATER ASSEMBLY & HEATER CORE