HVAC System - Heater System Ford Econoline I

MAIN HEATER SYSTEM

Heating system is blend-air type. Major components of system include blower assembly, plenum assembly, control panel, air ducts, registers, and temperature and function controls. The blower assembly is located in engine compartment. All other components are located in passenger compartment.

AUXILIARY HEATER SYSTEM

Some models are equipped with a recirculating air-type auxiliary heating system. System components include auxiliary unit assembly and airflow duct assembly. (Scheme 1)

Control panel is mounted in dashboard and contains function selector lever, temperature control module and lever, and blower control switch. An optional control panel mounted in the headliner at rear of vehicle is available. Optional control panel permits local control over auxiliary heater. Driver may override rear control panel. Vehicles with rear heater have 2 blower switches which work independently of one another.

Blower Switches

Control panel mounted front and rear blower switches have 4 positions: low speed, medium-high speed, medium-low speed and high speed. Rear blower switch can be overridden by blower switch on instrument panel. Auxiliary switch also has an OFF position. When function selector switch is in OFF position, blowers will not operate.

Function Selector Switch

The function selector switch can be placed in OFF, vent, floor, mix and defrost positions. The position of function selector switch determines whether function doors are open, partially open or closed. Function doors direct airflow to selected outlets. The 3 vacuum motors and doors are outside/recirculated air, defrost/panel and defrost/floor. See VACUUM DIAGRAMS .

FUNCTION SELECTOR MODES

Note. The function selector switch does not affect the temperature blend door. Any desired temperature, from full cool to full warm, can be set regardless of which function control mode is selected.

OFF

In OFF mode, full vacuum is applied to outside/recirculated air and floor/defrost vacuum motors. Vacuum is not applied to panel/defrost vacuum motor. Blower motor is off. Temperature can be adjusted as desired. Recirculated air is directed to floor outlets.

Vent

In vent mode, outside air is allowed into system. Vacuum is not applied to outside/recirculated air vacuum motor. Full vacuum is applied to panel/defrost and floor/defrost vacuum motors. Airflow is directed to panel outlets. Blower motor speed and temperature can be adjusted to desired settings.

Floor

In floor mode, outside air is allowed through system. Vacuum is not applied to outside/recirculated air vacuum motor. Full vacuum is applied to floor/defrost vacuum motor. Vacuum is not applied to panel/defrost vacuum motor. Airflow is routed to floor outlets. Blower motor speed and temperature can be adjusted to desired settings.

Mix

In this mode, outside air is allowed into system. Vacuum is not applied to outside/recirculated air and panel/defrost vacuum motors. The panel/defrost and floor/defrost vacuum motors receive partial vacuum, allowing equal outlet airflow. Blower motor speed and temperature can be adjusted to desired settings.

Defrost

In defrost mode, outside air is routed through system and out defrost outlets. Vacuum is not applied to outside/recirculated air, floor/defrost and panel/defrost vacuum motors. Blower motor speed and temperature can be adjusted to desired settings.

TEMPERATURE CONTROL SWITCH

Temperature control switch is part of a temperature control module, attached to control frame with 2 screws. The module contains a printed circuit board and a linear potentiometer. The potentiometer switch is mechanically coupled to potentiometer wiper.

The temperature blend door actuator contains a reversible electric motor and a potentiometer. The potentiometer wiper is connected to the actuator output shaft and moves with the output shaft to indicate position of temperature blend door.

Battery voltage is applied to ends of each potentiometer. The voltage available at each wiper indicates position of the potentiometer. The actuator wiper voltage is sent to the control module and matched with the wiper voltage of the module potentiometer. The printed circuit board then drives the actuator motor in whichever direction is necessary to make the actuator wiper voltage agree with the control wiper voltage.

BLOWER MOTOR INOPERATIVE

Turn ignition on and blower switch momentarily to each position. Check for voltage and ground at blower motor connector. If voltage and ground are present, test blower motor. If voltage is not present, check fuse No. 13 (15-amp) at instrument panel fuse panel and fuse No. 13 (50-amp) at engine compartment fuse box, replace fuse(s) as necessary. Check function selector switch and wiring. If ground is not present, check blower resistor, blower switch and wiring.

BLOWER MOTOR ONLY RUNS IN LOW

Check blower switch. Check wiring for open circuit. Check ground circuit for open circuit. Check for open blower motor resistor.

BLOWER MOTOR ONLY RUNS IN HIGH

Check for open blower motor resistor. Check for open thermal limiter. Check blower switch.

AIR FLOWS FROM WRONG OUTLETS

Test vacuum check valve. Check for vacuum leaks and inoperative vacuum motor. Check for correct vacuum hose routing. (Scheme 2)

INSUFFICIENT HEAT

Ensure cooling system is operating properly. Check heater system hoses and heater core for coolant flow. Test vacuum check valve. Check temperature control switch. Check wiring between temperature control switch and blend door actuator.

ERRATIC FUNCTION MODE SELECTION

1. Check for vacuum source at engine manifold and vacuum canister. Ensure check valve is installed correctly. Check for leak at vacuum controller. Ensure all vacuum hoses are correctly routed and connections are tight. (Scheme 2)
2. Check vacuum motors and vacuum hoses for leaks and kinks. Check all mode doors and blower motor for binding and foreign material.

TESTING

Note. For testing of heater system components not covered in this article, see MANUAL A/C-HEATER SYSTEMS - "E" SERIES article.

BLOWER MOTOR

Unplug blower motor harness connector. Using a jumper wire, connect battery voltage to blower motor connector Orange/Red wire terminal. Connect a second jumper wire from ground to blower motor connector Orange/Black wire terminal. Replace motor if it does not operate at high speed.

BLOWER MOTOR RESISTOR

Note. Blower motor resistor controls medium-high, medium-low and low blower speeds. Blower motor resistor resistance test specifications are the same for both main and auxiliary systems.

Remove blower motor resistor. See BLOWER MOTOR RESISTOR under REMOVAL & INSTALLATION. Measure resistance between indicated terminals. See BLOWER MOTOR RESISTOR RESISTANCE TEST table. If resistance is not as specified, replace resistor.

BLOWER MOTOR RESISTOR RESISTANCE TEST

MAIN BLOWER MOTOR SWITCH

Remove control panel from dash. See MAIN CONTROL PANEL under REMOVAL & INSTALLATION. Check for continuity in all switch positions. See MAIN BLOWER MOTOR SWITCH CONTINUITY table. If continuity is not as specified, replace main blower motor switch.

MAIN BLOWER MOTOR SWITCH CONTINUITY

REAR BLOWER MOTOR SWITCH

Remove control switch from overhead console. See REAR (AUXILIARY) CONTROL PANEL under REMOVAL & INSTALLATION. Check for continuity in all switch positions. See REAR BLOWER MOTOR SWITCH CONTINUITY table. If continuity is not as specified, replace rear blower motor switch.

REAR BLOWER MOTOR SWITCH CONTINUITY

Place function selector switch in specified position. Using a vacuum gauge, check for presence or absence of vacuum as specified. (Scheme 2) If test results are not as specified, check for kinked or broken vacuum lines. If vacuum lines are okay, replace function selector valve.

REMOVAL & INSTALLATION

Disconnect battery cables. Remove battery and battery tray. Disconnect blower motor lead at wiring harness. Remove blower motor housing tube. Remove ground wire mounting screw from firewall and 4 screws from blower motor mounting plate. Carefully remove blower motor assembly. To install, reverse removal procedure.

Removal & Installation (Front Blower Motor)

Locate blower resistor in engine compartment. Unplug electrical connector from resistor. Remove 2 screws and resistor from heater case. To install, reverse removal procedure. Check blower motor operation.

Removal & Installation (Rear Blower Motor)

Remove bench seat and service cover. Disconnect wiring harness at resistor assembly. Remove mounting screws and resistor assembly. To install, reverse removal procedure. Check blower motor operation.

Remove trim applique and 3 screws retaining control panel to mounting bracket. Carefully pull control panel from opening. Disconnect electrical connectors, vacuum hoses, illumination bulb and temperature control module. Remove push-on vacuum hose retaining clips from function selector valve, and remove harness. To install, reverse removal procedure.

Carefully pry control panel away from overhead console. Disconnect light and blower motor switch connectors from switch. Remove control knob. Remove screw and blower motor switch. To install, reverse removal procedure.

1. Drain cooling system. Disconnect negative battery cable. Remove heater hoses from heater core in engine compartment. Plug hoses. Remove engine cover. Remove instrument panel finish panel.
2. Remove 7 screws from heater core cover. Remove heater core cover. Remove screw and retaining bracket at bottom of heater core. Remove heater core and seal from case. To install, reverse removal procedure. Install NEW case seal. Refill and leak test cooling system.

1. Disable air bag system. See AIR BAG SYSTEM SAFETY article in GENERAL SERVICING. Place wheels in straight-ahead position. Remove back cover plugs from driver-side air bag module. Remove screws from module. Disconnect horn connector. Disconnect air bag sliding contact connector. Remove driver-side air bag.
2. Remove passenger-side finish panel and finish panel reinforcement. Remove passenger-side air bag module retaining nuts. Carefully slide flat bladed screwdriver under right bottom edge of air bag module door and lift up. Separate remainder of door using finger pressure. Disconnect air bag electrical connector. Remove passenger-side air bag module.
3. Remove engine cover. Remove steering wheel bolt. Using 2-jaw puller, remove steering wheel. Remove steering column molding. Unscrew steering column release lever. Rotate ignition switch to RUN position. Use an 1/8" drift to press lock cylinder retaining pin through access hole in column shroud. Remove lock cylinder. Remove clockspring. Remove steering column shrouds.
4. Remove lower trim panel and knee brace retaining bolts. Remove steering column support retaining nuts. Disconnect shift indicator cable and cable loop from shift tube hook. Remove 2 retaining screws, electrical connectors and multifunction switch. Remove pinch bolt from steering column universal joint. Disconnect shift cable from selector lever pivot arm.
5. Remove shift cable by pushing tab on cable in and sliding cable off bracket. Disconnect ignition switch. Lower steering column bend bracket and disconnect electrical connectors. Support steering column and remove 4 column retaining nuts. Remove steering column.
6. Remove instrument panel cowl top screws. Remove upper center instrument panel access panel. Disconnect vacuum harness connector. Remove left upper access panel and remove instrument panel cowl top nut. Remove instrument panel dash brace.
7. From inside engine compartment, position coolant reservoir aside. Remove lower main wiring assembly bulkhead connector bolt. Disconnect bulkhead connector clips and remove bulkhead. From inside vehicle, remove right side cowl trim panel. Disconnect electronic crash sensor electrical connector. Disconnect 3 cowl side wiring connectors.
8. Disconnect antenna from radio and antenna wire from instrument panel clip. Remove 4 bolts attaching instrument panel to cowl. Have an assistant support panel, and move it rearward.
9. Disconnect any remaining wires and components. Working with an assistant, remove instrument panel through driver-side door. To install, reverse removal procedure.

1. Disconnect negative battery cable. Remove instrument panel. See «INSTRUMENT PANEL»(/ford/econoline/i-1985-2013/remont/heater/#hvac-system-heater-system) . Disconnect vacuum hoses from panel/defrost vacuum motor and floor/defrost vacuum motor. Remove retainers attaching center register duct and heater air outlet duct to plenum.
2. Separate plenum from heater housing, center register duct and heater air outlet duct. Remove plenum assembly. Remove vacuum motors from plenum. To install, reverse removal procedure.

Remove third, fourth and fifth bench seats (if equipped). Drain cooling system. Disconnect heater hoses located under left side of body. Disconnect rear heater assembly harness connectors. (Scheme 1) Remove mounting bolts and lift assembly off locating dowel pin. Remove assembly while guiding heater hoses through from underbody. To install, reverse removal procedure.

Scheme 1

1. Remove third, fourth and fifth bench seats (if equipped). Remove auxiliary heater cover attaching screws, and remove cover assembly. Remove strap retaining heater core in auxiliary heater case.
2. Drain coolant from radiator. Disconnect heater hoses from auxiliary heater core. Plug openings. Disengage wire assembly from auxiliary heater core seal. Slide heater core and seal assembly out of case. To install, reverse removal procedure. Fill cooling system.

Scheme 2

Main & Auxiliary Heater System Wiring Diagram ("E" Series). Scheme 3

See also:
• VACUUM DIAGRAMS