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Heater System: Other Ford Probe II

Heater ~2290 words

Temperature Control Knob

A cable connects temperature control knob to temperature blend door. With knob in cool position, air by-passes heater core. With knob in warm position, air is directed through heater core. With knob in intermediate positions, heated air is blended with cooler incoming air to achieve desired temperature.

Function Selector Knob

Function selector knob operates recirculated/fresh air door, floor door, panel door and defrost door vacuum motors. Selection of VENT, FLOOR, OFF, MIX or DEFROST directs airflow to the chosen outlets.

Blower (Fan) Switch

The blower motor operates in 4 speeds, ranging from low to high.

VENT

In VENT mode, outside air is allowed into system. Vacuum is not applied to the recirculated/fresh air door vacuum motor. Vacuum is not applied to floor door vacuum motor. Full vacuum is applied to panel and defrost door vacuum motors. Airflow is routed to panel outlets. Air temperature can be adjusted to desired setting. Blower motor is on and can be adjusted to desired speed.

FLOOR

In FLOOR mode, outside air is routed through system to floor outlets. Vacuum is not applied to the recirculated/fresh air door vacuum motor. Full vacuum is applied to floor door vacuum motor and defrost door vacuum motor (defrost vent closed). Blower motor speed and temperature can be adjusted to desired settings.

OFF

In OFF mode, recirculated/fresh air door vacuum motor receives full vacuum (recirculate mode). Defrost and floor vacuum motors receive full vacuum, closing off airflow to defroster outlets. Vacuum is not applied to panel door vacuum motor. All recirculated airflow is directed to the floor outlets. Temperature can be adjusted to desired setting. Blower motor is off.

MIX

In MIX mode, outside air is allowed into systemand is routed to all outlets. Vacuum is not applied to recirculated/fresh air, panel and defrost door vacuum motors. The floor door motor receives partial vacuum. Blower motor speed and temperature can be adjusted to desired settings.

DEFROST

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

TEMPERATURE CONTROL CABLE

Turn temperature control knob to maximum warm position. Remove glove box door to access cable. Remove control cable from mounting brace. With cable attached to door lever pin, push door lever down to its last stop. Secure cable housing to cable mounting brace. Test heating system for proper operation. Install glove box.

HEATER BLOWER MOTOR DOES NOT RUN AT ANY SPEED

  1. Check Fuses Turn ignition off. Locate 15-amp ENGINE fuse in interior fuse junction panel located behind left side kick panel. Locate 40-amp HEATER fuse in main fuse junction panel located behind battery. If fuses are okay, go to step 4). If fuse(s) are not okay, go to next step.
  2. Check System Turn ignition off and replace blown fuse(s). Turn ignition on. If fuse(s) blow again, go to next step. If fuse(s) do not fail again, go to step 4).
  3. Check For Short(s) To Ground Turn ignition off. Disconnect interior fuse junction panel 10-pin connector. Remove 40-amp HEATER fuse from main fuse junction panel. Disconnect blower motor No. 1 relay connector, located at right front side of radiator. Measure resistance between ground and fuse junction panel 10-pin connector terminal No. 2 (Black/White wire). Measure resistance between ground and 40-amp HEATER fuse holder left terminal (Blue wire). If resistance is greater than 5 ohms, repair short to ground. If resistance is less than 5 ohms, restore connections, install fuses, and go to next step.
  4. Check Heater Blower Motor Turn ignition off and disconnect heater blower motor 2-pin connector. Connect battery voltage to heater blower motor 2-pin connector White wire and ground to connector Blue/Orange wire. If heater blower motor operates, go to next step. If heater blower motor does not operate, replace blower motor.
  5. Check Heater Blower Motor Switch Turn ignition off and disconnect heater blower motor switch connector. Measure resistance between heater blower motor switch terminals with switch in each specified position. See «HEATER BLOWER MOTOR SWITCH TESTING»(ref-39336-S25108359792001011200000) table. If resistance is as specified, go to next step. If resistance is not as specified, replace heater blower motor switch. HEATER BLOWER MOTOR SWITCH TESTING Switch Terminals Test Between Ohms Position LO All (1) 10,000 2nd BLU/YEL & BLU (2) 5 2nd All Others (1) 10,000 3rd BLU/YEL & BLU (2) 5 3rd BLU/YEL & YEL/BLK (2) 5 3rd BLU & YEL/BLK (2) 5 3rd All Others (1) 10,000 HI BLU/YEL & YEL/BLK (2) 5 HI BLU/YEL & BLU/WHT (2) 5 HI YEL/BLK & BLU/WHT (2) 5 HI All Others (1) 10,000 (1) Greater than. (2) Less than.
  6. Check Mode Selector Switch Disconnect mode selector switch connector, located behind control panel. Measure resistance between mode selector switch Blue/Yellow wire and Black wire terminals. With switch in OFF position, resistance should be more than 10,000 ohms. With switch in any other position, resistance should be less than 5 ohms. If resistance is as specified, go to next step. If resistance is not as specified, replace mode selector switch.
  7. Check Mode Selector Switch Ground Disconnect mode selector switch and measure resistance between mode selector switch connector Black wire and ground. If resistance is less than 5 ohms, reconnect mode selector switch connector and go to next step. If resistance is not less than 5 ohms, repair Black wire between switch connector and ground.
  8. Check Blower Motor No. 1 Relay Turn ignition off. Locate blower motor No. 1 relay at right side of radiator and disconnect connector. Connect battery voltage to blower motor No. 1 relay Black/White wire terminal. Connect ground lead to blower motor No. 1 relay Black/Red wire terminal. Measure resistance between blower motor No. 1 relay Blue wire and White wire terminals. If resistance is less than 5 ohms, go to next step. If resistance is not less than 5 ohms, replace blower motor No. 1 relay.
  9. Check Power To Blower Motor No. 1 Relay Turn ignition off. Locate blower motor No. 1 relay at right side of radiator and disconnect connector. Turn ignition on. Measure voltage between blower motor No. 1 relay connector Blue wire terminal and ground, and between Black/White wire terminal and ground. If voltage is more than 10 volts, turn ignition off and go to next step. If voltage is not more than 10 volts, repair wire circuit(s).
  10. Check Blower Motor No. 1 Relay Ground Turn ignition off. Locate blower motor No. 1 relay at right side of radiator and disconnect connector. Measure resistance between ground and blower motor No. 1 relay connector Black/Red wire terminal. If resistance is less than 5 ohms, go to next step. If resistance is not less than 5 ohms, repair Black/Red wire circuit.
  11. Check Heater Blower Motor Resistor Turn ignition switch off and disconnect blower motor resistor connector. Using a DVOM, measure resistance between terminals indicated in «BLOWER MOTOR RESISTOR TESTING»(ref-39336-S30084291872001011200000) table. If resistance is as specified, go to next step. Replace heater blower motor resistor if resistance readings are not as specified. BLOWER MOTOR RESISTOR TESTING Terminal No. (Wire Color) Ohms 1 (GRN/RED) & 4 (BLU/WHT) 2.76 1 (GRN/RED) & 2 (BLU) 1.69 2 (BLU) & 3 (RED/BLK) 0.69 3 (RED/BLK) & 4 (BLU/WHT) 0.38
  12. Check Wire Between Blower Motor No. 1 Relay & Heater Blower Motor Turn ignition off. Locate blower motor No. 1 relay at right side of radiator and disconnect connector. Disconnect heater blower motor connector. Measure resistance between White wire terminal at blower motor No. 1 relay connector and heater blower motor. If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, repair White wire circuit.
  13. Check Wire Between Heater Blower Motor & Heater Blower Motor Resistor Disconnect heater blower motor and heater blower motor resistor connectors. Measure Blue/Orange wire resistance between heater blower motor connector and heater blower motor resistor connector. If resistance is less than 5 ohms, repair Blue/Yellow wire circuit between heater blower motor switch and mode selector switch. If resistance is greater than 5 ohms, repair Blue/Orange wire.

Check Heater Blower Motor Switch

Turn ignition off and disconnect heater blower motor switch connector. Measure resistance between heater blower motor switch terminals with switch in each specified position. See HEATER BLOWER MOTOR SWITCH TESTING table under HEATER BLOWER MOTOR DOES NOT RUN AT ANY SPEED.

If resistance is as specified, repair short to ground in Blue/Orange wire or Blue/White wire between heater blower motor, heater blower motor switch, and heater blower motor resistor. If resistance is not as specified, replace heater blower motor switch.

Check Heater Blower Motor Resistor

Turn ignition switch off and disconnect blower motor resistor connector. Using a DVOM, measure resistance between terminals indicated in BLOWER MOTOR RESISTOR TESTING table under HEATER BLOWER MOTOR DOES NOT RUN AT ANY SPEED. If resistance is as specified, repair open in Green/Red wire between heater blower motor resistor and mode selector switch. Replace heater blower motor resistor if resistance readings are not as specified.

Check Mode Selector Switch

Disconnect mode selector switch connector, located behind control panel. Measure resistance between mode selector switch Blue/Yellow wire and Black wire terminals. If resistance is greater than 10,000 ohms, repair short to ground in Blue/Yellow wire. If resistance is less than 10,000 ohms, replace mode selector switch.

Turn ignition off and disconnect heater blower motor switch connector. Measure resistance between heater blower motor switch terminals with switch in each specified position. See HEATER BLOWER MOTOR SWITCH TESTING table under HEATER BLOWER MOTOR DOES NOT RUN AT ANY SPEED. If resistance is as specified, repair open in Blue/Yellow wire between heater blower motor switch and mode selector switch. If resistance is not as specified, replace heater blower motor switch.

HEATER BLOWER MOTOR STAYS IN LOW SPEED W/ HEATER BLOWER MOTOR SW IN 2ND SPEED POSITION

  1. Check Heater Blower Motor Switch Turn ignition off and disconnect heater blower motor switch connector. Measure resistance between heater blower motor switch terminals with switch in each specified position. See «HEATER BLOWER MOTOR SWITCH TESTING»(ref-39336-S30084291872001011200000) table under HEATER BLOWER MOTOR DOES NOT RUN AT ANY SPEED. If resistance is as specified, go to next step. If resistance is not as specified, replace heater blower motor switch.
  2. Check Heater Blower Motor Resistor Turn ignition switch off and disconnect blower motor resistor connector. Using a DVOM, measure resistance between terminals indicated in «BLOWER MOTOR RESISTOR TESTING»(ref-39336-S30084291872001011200000) table under HEATER BLOWER MOTOR DOES NOT RUN AT ANY SPEED. If resistance is as specified, repair open in Blue wire between heater blower motor switch and heater blower motor resistor. Replace heater blower motor resistor if resistance readings are not as specified.

HEATER BLOWER MOTOR STAYS IN 2ND SPEED W/ HEATER BLOWER MOTOR SW IN 3RD SPEED POSITION

  1. Check Heater Blower Motor Switch Turn ignition off and disconnect heater blower motor switch connector. Measure resistance between heater blower motor switch terminals with switch in each specified position. See «HEATER BLOWER MOTOR SWITCH TESTING»(ref-39336-S25108359792001011200000) table under HEATER BLOWER MOTOR DOES NOT RUN AT ANY SPEED. If resistance is as specified, go to next step. If resistance is not as specified, replace heater blower motor switch.
  2. Check Blower Motor No. 2 Relay Turn ignition off. Locate heater blower motor No. 2 relay on heater blower motor assembly and disconnect relay connector. Apply battery voltage to heater blower motor No. 2 relay Black/Yellow wire terminal. Connect ground lead to heater blower motor No. 2 relay Yellow/Black terminal. Measure resistance between heater blower motor No. 2 relay Blue/Yellow wire and Blue/White wire terminals. If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, replace heater blower motor No. 2 relay.
  3. Check Power To Blower Motor No. 2 Relay Turn ignition off. Disconnect blower motor No. 2 relay connector. Turn ignition on. If more than 10 volts is present at blower motor No. 2 relay Black/Yellow wire terminal, go to next step. If less than 10 volts is present at blower motor No. 2 relay Black/Yellow wire terminal, repair Black/Yellow wire.
  4. Check Heater Blower Motor Resistor Turn ignition switch off and disconnect heater blower motor resistor connector. Using a DVOM, measure resistance between terminals indicated in «BLOWER MOTOR RESISTOR TESTING»(ref-39336-S30084291872001011200000) table under HEATER BLOWER MOTOR DOES NOT RUN AT ANY SPEED. If resistance is as specified, go to next step. If resistance readings are not as specified, replace heater blower motor resistor.
  5. Check Wire Between Blower Motor No. 2 Relay & Heater Blower Motor Switch Turn ignition off. Disconnect blower motor No. 2 relay and heater blower motor switch connectors. Measure resistance of Yellow/Black wire between heater blower motor No. 2 relay and heater blower motor switch connectors. If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, repair Yellow/Black wire.
  6. Check Wire Between Blower Motor No. 2 Relay & Heater Blower Motor Resistor Turn ignition off. Disconnect heater blower motor No. 2 relay and heater blower motor resistor connectors. Measure resistance of Red/Black wire between heater blower motor No. 2 relay and heater blower motor resistor connectors. If resistance is less than 5 ohms, repair open in Blue/Yellow wire between heater blower motor No. 2 relay and mode selector switch. If resistance is greater than 5 ohms, repair Red/Black wire.

Turn ignition off and disconnect heater blower motor switch connector. Measure resistance between heater blower motor switch terminals with switch in each specified position. See HEATER BLOWER MOTOR SWITCH TESTING table under HEATER BLOWER MOTOR DOES NOT RUN AT ANY SPEED. If resistance is as specified, repair open in Blue/White wire between heater blower motor switch and heater blower motor resistor. If resistance is not as specified, replace heater blower motor switch.

INSTRUMENT PANEL

WARNINGTo avoid injury from accidental air bag deployment, read and carefully follow all SERVICE PRECAUTIONS and DISABLING & ACTIVATING AIR BAG SYSTEM procedures in AIR BAG article in ACCESSORIES/SAFETY EQUIPMENT section.

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