CONTROL PANEL
On Dakota, control panel contains a TEMP control lever; a PANEL, BI-LEV, FLOOR and DEFROST mode lever; and a 4-position fan switch. On Pickup, Ramcharger and Van, control panel contains a COOL-to-WARM temperature control lever; an OFF, HEAT and DEFROST mode lever; and a 4-position fan switch. (Scheme 15)
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.
MODE CONTROL LEVER
Mode lever positions mode door in air distribution duct. Door directs air to heater or defroster ducts.
FAN SWITCH
Four-position switch allows operation of fan at 3 different speeds. Vertically mounted, lever-type switch has OFF, LOW, MEDIUM and HIGH positions.
Scheme 14
Scheme 15
CONTROL CABLE
Note. See MODE CONTROL CABLE , TEMPERATURE CONTROL CABLE R & I and MODE & TEMPERATURE CONTROL CABLE under REMOVAL & INSTALLATION.
TOO MUCH HEAT
Blend-air or temperature door binding or misdirected. Improperly adjusted, disconnected, kinked or broken temperature control cable. Thermostat stuck or opening at too high a temperature. Temperature door misdirected or binding.
BLOWER DOES NOT OPERATE AT ALL SPEEDS
Faulty resistor block or blower switch. Defective wiring connections at resistor block and/or blower switch.
BLOWER INOPERATIVE
Fuse blown. Motor inoperative. Ground wire or blower switch faulty. Open in motor or resistor.
BLOWER OPERATES ON HIGH ONLY
Fuse blown. Short in wiring. Defective resistor block or resistor switch.
INSUFFICIENT HEAT
Obstructed outlets. Temperature door binding. Temperature door misadjusted. Kinked or unattached temperature control cable. Mode door binding or improperly adjusted. Defective mode door actuator. Defective mode switch. Kinked or plugged heater hoses. Heater core plugged. Defective heater control valve. Engine temperature low. Air in heater core. Hose connections reversed. Insufficient coolant.
Dakota
See BLOWER MOTOR .
Removal - Pickup & Ramcharger
- Disconnect battery ground cable. Remove coolant hoses on engine side, and plug hoses and inlets. Remove right cowl side trim panel (if equipped). Remove glove box by removing 4 mounting screws at base, and swing box out from bottom to avoid catch and stops. see scheme 3
- Remove structural brace through glove box opening. Remove right half of instrument panel lower reinforcement. Be sure to disconnect ground strap.
- Disconnect control cables. Disconnect blower motor wires on engine side. Remove wires from resistor block. Remove screw attaching heater to cowl. Remove attaching nuts on engine side, and remove heater assembly.
- Remove 15 screws and mode crank door to separate cover from housing. Carefully slide heater core out. Peel back instrument panel seal below cover. Remove retaining screws, and remove cover from blower motor assembly. Separate fan from motor, and separate motor from housing.
MODE & TEMPERATURE CONTROL CABLE
Note. Control cables are fastened to heater control with snap-in flags.
- Remove faceplate. See «FACEPLATE»(ref-38788-S00431083612001011200000). Open glove box past stops. Remove control unit from instrument panel. Remove cables from control lever pins, and remove flags from retainers.
- Detach cables from heater assembly by removing self-adjusting clips from crank arms and removing flags from retainers. Remove cable assemblies through glove box opening. Using a tube or rod, pry self-adjusting clip from cable core. see scheme 5