Heater System Ford Bronco II I

DESCRIPTION

The heater-ventilation system is a blend-air design and consists of the following major components: heater blower assembly, plenum, air distribution ducts and register, control assembly, control cables and defroster nozzle. The heater blower assembly is located in engine compartment and contains the blower motor, wheel, and blower resistor.

The plenum is located in the passenger compartment and contains the heater-defroster door, temperature blend door, vent-heater door, air shut-off door and heater core. The defroster nozzle is a 3-outlet nozzle and connects to defroster outlet and plenum.

HEATER-VENTILATION SYSTEM CONTROLS

When the outside air function control lever is moved to the "VENT-HEAT" position, the heater ventilation system receives outside air from the cowl top grille for system operation. Outside air enters the blower from the cowl air intake.

Air is forced through and/or around the heater core on the plenum. Air is then directed either to the floor, defroster nozzle, to both the floor and the defroster nozzle, to the instrument panel registers, or to the registers and floor, depending on the function control lever setting.

Air flow volume is controlled by a blower switch and a resistor assembly to provide 4 blower operating speeds plus an "OFF" position. Outside air flow can be shut off by moving the outside air function control lever to "OFF" position and turning blower switch to "OFF" position.

The system is controlled by manually adjusted cables connected between the control assembly, through cams to the air door in the plenum. The function lever operates heater-defroster door and vent-heater door located in plenum be means of a cable and cam. The temperature control lever operates temperature blend door in plenum.

Temperature Lever

When temperature lever is in "COOL" position, blend air door directs outside air to by-pass heater core. When in "WARM" position, air is directed through heater core. Positioning of lever in intermediate positions results in a blending of cool and warm air to produce air of desired temperature.

Mode Selector Lever

In "VENT" position, air flow is from instrument panel outlets. As mode control lever is moved toward "HI-LO" position, air flow is split between instrument panel outlets and floor outlets.

In "HEAT" position, blend air door directs air to floor outlets with a small amount to defroster outlets. In "MIX" position, air is divided between floor and defroster outlets. In "DEFROST" position, air is directed to defroster outlets with a small amount to floor outlets.

Blower Switch

Blower switch has "OFF" and "HI" positions on all models. Bronco II and Ranger models have 3 intermediate positions, while all other models have 2 intermediate positions.

CONTROL CABLES

Note. Check condition of cables before making adjustments.

Mode, Outside Air & Temperature Control Cables

1. Drop glove box by squeezing sides together to disengage tabs and let box hang free. Working through glove box opening, remove cable housing from metal clip on top of plenum by depressing clip tab and pulling cable up.
2. Cable core wire end loop should remain attached to control cam on plenum. To adjust temperature control cable, move control lever to "COOL" position and hold.
3. Push cable housing (Blue) to seat blend door (push until you feel resistance). Install cable housing to clip by pushing it from top until it snaps into place.
4. To adjust mode control cable, move control lever to "DEFROST" position and hold. Pull on cam jacket until cam travel stops. Reinstall cable housing to clip by pushing it from top until it snaps into place.
5. To adjust outside air cable, move outside air control lever to "OFF" position and hold. Set door arm (White) in down position (door closed to shut off air flow).
6. With cable end attached to door arm, reinstall cable to clip. Turn blower switch to "HI" position and check for proper operation. Install glove box.

BLOWER MOTOR VOLTAGE TEST

Place temperature lever in mid-range position. Place mode lever in "VENT" position. Insert probes of voltmeter into connector at rear of blower motor and make contact with wire terminals. With engine running, voltage should be as specified for each switch position. See BLOWER TEST SPECIFICATIONS table.

BLOWER MOTOR CURRENT DRAW TEST

1. Disconnect blower motor electrical connector. Connect ammeter between left (positive) terminal on motor and corresponding terminal of wire harness connector.
2. Place temperature control lever in mid-range position. Place mode lever in "VENT" position.With engine running, current draw (amperage) should be as specified for each blower speed. See «BLOWER TEST SPECIFICATION»(/ford/bronco-ii/i-1984-1990/remont/heater/#heater-system) table

Removal

1. Disconnect battery ground cable. Remove radio control knobs from radio shafts. Remove 4 screws attaching top of cluster finish panel to upper finish panel pad.
2. Remove cigar lighter. Remove center and left instrument trim panels. Pull headlight switch to on and detach left instrument trim panel enough to allow access to cluster finish panel lower attaching screws.
3. Remove 4 screws attaching bottom of cluster finish panel to instrument panel. Lift cluster finish panel away from instrument panel. Remove 4 screws attaching control panel to instrument panel.
4. Pull control panel through instrument panel opening far enough to allow removal of electrical connectors. Remove connectors.
5. Working from bottom of control panel using a screwdriver, release mode control cable (Black) snap-in flag from control bracket.
6. Pull enough cable through instrument panel opening until mode control cable can be held vertical to control panel. Remove control cable from mode control lever.
7. Working from top of control panel, using needle nose pliers, release temperature control cable (Blue) and outside air control cable (White). Rotate control panel 90° down. Disconnect temperature and outside air control cables from control levers. Remove control panel.

Installation

To install, reverse removal procedure. Ensure proper operation of control assembly.

Heater Control Panel Removal (Bronco II & Ranger Models) Release control cable snap-in flags with needle-nose pliers. Courtesy of Ford Motor Co. Scheme 1

1. Disconnect battery ground. Remove heater blower assembly. Remove heater hoses from heater core tubes and plug openings. In engine compartment, remove 4 nuts from plenum studs at dash panel.
2. Remove 3 screws from steering column lower finish panel and remove panel. Remove 2 attaching screws and remove steering column shroud. Remove headlight and radio knobs.
3. Remove cigar lighter. Unsnap 3 finish trim panels from bottom edge of instrument panel. Remove ashtray. Remove 2 bolts from steering column center support bracket. Remove 3 bolts from base of steering column.
4. Remove 4 screws from underneath top front edge of instrument panel pad. Remove 3 screws each from defroster air outlets. Remove bolt from instrument panel lower center brace.
5. Remove screws from extreme bottom ends of instrument panel. Remove hex screw from instrument panel pad and emergency brake release lever support bracket. Remove 2 screws from hood release lever support bracket.
6. Remove nut from instrument panel pad support bracket located in steering column opening. Remove 4 attaching screws and instrument panel cluster. Remove 3 screws from above glove box.
7. Remove attaching screws and radio speaker grilles. Remove radio speakers. Remove instrument panel pad. Remove 3 screws from top of instrument panel. Disconnect speedometer cable.
8. Remove bolt from instrument panel and parking brake release lever support bracket. Disconnect hard shell connector at lower side behind instrument panel.
9. Remove radio antenna wire from clip attached to defroster nozzle. Disconnect control cables at plenum. Remove instrument panel from vehicle. Pull plenum rearward from dash panel and remove from vehicle.

To install, reverse removal procedure.

Scheme 2

1. Disconnect battery ground. On vehicles equipped with 2.8L engine, remove vacuum reservoir and solenoid box cover in front of blower motor.
2. For vehicles equipped with 2.3L diesel engine, remove vacuum reservoir and washer in front of blower motor. For vehicle equipped with 2.3L EFI engine, remove air cleaner in front of blower motor.
3. On all vehicles disconnect wire harness connector from blower motor by pushing down on connector tabs and pulling connector off motor. Disconnect blower motor cooling tube at blower motor.
4. Remove 3 screws attaching blower motor and wheel to heater blower assembly. Holding cooling tube aside, pull blower motor and wheel from heater blower assembly and remove from vehicle. Remove blower wheel hub clamp from motor shaft. Then, pull blower wheel from motor shaft.

To install, reverse removal procedure.

HEATER CORE

Note. These procedures are for vehicles with heater systems only. For replacement on vehicles equipped with manual A/C-heater systems, see appropriate article in MANUAL A/C-HEATER SYSTEMS section.

1. Drain coolant from radiator. Disconnect heater hoses from heater core and plug openings. Remove 5 screws from heater core access cover on plenum assembly.
2. Remove access cover. Pull heater core rearward and down, removing from plenum.

To install, reverse removal procedure.

BLOWER TEST SPECIFICATIONS

BLOWER TEST SPECIFICATIONS

TROUBLE SHOOTING & DIAGNOSIS

See HEATER SYSTEMS, FORD MOTOR CO. PASSENGER CARS & TRUCKS

TROUBLE SHOOTING & DIAGNOSIS in this section.

Heater Wiring (Bronco, Bronco II, Ranger & "F" Series). Scheme 3

See also:
• BLOWER TEST SPECIFICATIONS