Blower Motor: Service and Repair

BLOWER MOTOR REPLACEMENT

Background Information

Vehicles built during 1975-1980 have a 3-speed field-wound blower motor.

Vehicles built during 1981-1993 have a 4-speed permanent magnet blower motor.

Only the later 4-speed permanent magnet blower motor (Part No. 3537220-0) is available as a spare part.

Blower Motor Housing

When installing a 4-speed permanent magnet motor (Part No. 3537220-0) into 1975-1984 Model Year Vehicle, modifications are required to the blower motor housing for proper fit of the new updated blower motor.

^ These modifications are addressed under the "HOUSING MODIFICATION" header below.

Additional Parts

When installing 4-speed permanent magnet motor (Part No. 3537220-0) into 1975-1982 Model Year Vehicles, additional parts are required for proper fit and operation of the new blower motor.

^ The additional parts needed for 1975-1982 vehicles are:

^ 1 Resistor, Part No. 1370240-2
^ 1 Switch, Part No. 1323849-8
^ 3 Screws, Part No. 969478-7

Blower Motor Wiring

The wiring of 1975-1982 Model Year Vehicles must be modified for proper operation of the new 4-speed blower motor/switch combination.

^ These modifications are addressed under the "WIRING MODIFICATION" header below. Updated wiring diagrams are included.

REMOVAL PROCEDURE

1. Disconnect the battery ground cable.

Center Console:

2. Remove sound insulation and center console side panels on both sides.

3. Remove radio.

4. Detach the control panel and central console.

Center Vents And Glove Compartment:

5. Remove or disconnect center air vents.

6. Disconnect wire connectors from the clock.

7. Remove glove compartment.

8. Remove air ducts for the center air vents.

On Right-hand (Passenger's) Side of Vehicle

Shutter Actuator Diaphragm Hoses:

NOTE: A 1975-1980 version is shown in the image. From 1981-1993 the air vents are also secured by a screw, this screw must be removed.

9. Remove air ducts.

10. Disconnect hoses to shutter actuator diaphragms.

Outer Fan Housing - Right Side:

11. Fold back the floor carpet.

12. Remove screw for the rear floor air duct. Move the duct to one side slightly.

13. Carefully remove outer fan housing clips using a flat blade screwdriver and remove the outer fan housing.

NOTE: It may be necessary to remove the support under the glove compartment to remove the outer fan housing.

14. Remove fan wheel.

Fan Switch Plug:

15. Remove the blower motor switch from the central console.

16. Disconnect electrical connector from the switch.

On Left-hand (Driver's) Side of Vehicle

Shutter Actuator Diaphragm Hoses:

NOTE: A 1975-1980 version is shown in the image. From 1981-1993 the air vents are also secured by a screw, this screw must be removed.

17. Remove air ducts.

18. Disconnect hoses to shutter actuator diaphragms.

Outer Fan Housing - Left Side:

19. Fold back the floor carpet.

20. Remove screw for the rear floor air duct. Move the duct to one side slightly.

21. Carefully remove outer fan housing clips using a flat blade screwdriver and remove the outer fan housing.

22. Remove fan wheel.

23. Remove three inner fan housing screws and inner fan housing.

24. Remove hose to shutter actuator diaphragm which operates left rear floor vent.

Blower Motor Retaining Plate:

NOTE: A 1975-1980 version is shown in the image.

25. Remove blower motor retaining plate.

26. Remove blower motor and ground lead.

HOUSING MODIFICATION

Housing Modification 1975-1980 Model Year Vehicles

^ For housing modification of 1981-1984 Model Year Vehicles proceed to the "1981-1984 Housing Modification" section.

^ For 1985-1993 Model Year Vehicles, or 1975-1984 Model Year Vehicles with previously modified heater housings proceed to "INSTALLATION PROCEDURE"

Oblong Sections:

1. File or grind inner sides of heater housing (arrows) to obtain correct fit of new blower motor. Grind only enough material to allow new blower motor to fit properly.

2. Grind down the three oblong sections (lines) with a machine or die grinder until flush with the surrounding area.

Heater Housing Hole Placement:

3. Drill a 16 mm (0.63 inch) hole in the bottom left side of the heater housing, 20 mm (0.79 inch) from the outer edge of the housing.

Drill from the inside the heater housing with a 90 degree drill adapter or from underneath by using a long drill bit and holding the drill against the transmission tunnel. A clean, round hole is needed otherwise condensation could occur if the vehicle is equipped with air conditioning.

4. Clean all surfaces thoroughly to prevent dirt from entering air ducts.

Housing Modification 1981-1984 Model Year Vehicles

^ For 1985-1993 Model Year Vehicles, or 1975-1984 Model Year Vehicles with previously modified heater housings proceed to "INSTALLATION PROCEDURE"

Round Spacer Tabs:

1. Grind down the round spacer tabs (lines) inside housing with a machine or die grinder until flush with the surrounding area.

Oblong Sections:

2. Some vehicles may also have the oblong sections (lines) which will need to be ground down until flush with the surrounding area as well.

3. If needed file or grind inner sides of heater housing (arrows) to obtain correct fit of new blower motor. Grind only enough material to allow new blower motor to fit properly.

4. Clean all surfaces thoroughly to prevent dirt from entering air ducts.

INSTALLATION PROCEDURE

Fan Switch Plug Wire Placement:

1. Mark wire locations on new switch connector. Disconnect wires from old connector.

2. DO NOT grind off a section of the plug. Pass the wires through the existing hole in the top of the heater housing. Reconnect wires into plug.

3. Place new motor (Part Number 3537220-0) in housing but do not install mounting screws at this time. In contrast to earlier motors, the new heater motor is not mounted on plastic bushings.

Resistor Wires And Upper Housing Grommet:

4. Pass the cables for the resistor through the upper hole in the heater housing. Fit the rubber grommet.

Blower Motor And Resistor Mounting:

5. Install the new blower motor. Secure the blower motor in position with the three mounting screws (Part Number 955143-3).

Use top mounting screw to secure resistor. Do not install any washers.

6. Insert wires and sheath through hole in bottom of housing (which was drilled for 1975-1980 models).

Take care not to kink or restrict wire sheath, air needed for fan motor ventilation flows through the rubber sheath.

Inner Fan Housing - Left Side:

7. Install inner fan housing and secure with the original screws.

8. Install heater control valve capillary tube in inner fan housing.

9. Install blower motor fan wheel.

10. Connect vacuum hose to left rear floor vent shutter actuator diaphragm.

Outer Fan Housing - Left Side:

11. Install outer fan housing and clips.

12. Install air duct for rear floor vent. Restore floor carpet back to it's original position.

Shutter Actuator Diaphragm Hoses:

13. Connect air ducts.

14. Connect vacuum hoses to shutter actuator diaphragms.

On Right-hand (Passenger's) Side of Vehicle

Outer Fan Housing - Right Side:

15. Install blower motor fan wheel.

16. Install outer fan housing and clips.

17. Install the support under the glove compartment (if removed).

18. Install air duct for rear floor vent. Restore floor carpet back to it's original position.

Shutter Actuator Diaphragm Hoses:

19. Connect air ducts.

20. Connect vacuum hoses to shutter actuator diaphragms.

WIRING PROCEDURE

^ For 1975-1982 Model Year Vehicles the wiring must be modified for proper operation of the new 4-speed blower motor/switch combination. Proceed to "WIRING MODIFICATION".

^ For 1983-1993 Model Year Vehicles the wiring does not need modifications, reinstall wiring as instructed below.

Fan Switch Plug Wire Placement:

1. Reconnect wires into the fan switch plug according to marks placed on switch connector during disassembly, refer to image.

2. Reconnect blower motor ground wire to bracket.

Fan Switch Plug:

3. Join connectors (arrow).

Fan Switch Plug:

4. Connect the connector to the switch.

5. Fit the switch to the central console.

6. Fit the switch knob.

7. Connect battery ground cable.

8. Test the operation of the new blower motor.

9. Reassemble/install remaining dash components in the reverse order of disassembly/removal.

WIRING MODIFICATION

^ For 1975-1982 Model Year Vehicles the wiring must be modified for proper operation of the new 4-speed blower motor/switch combination. Proceed to the proper Model Year modification header.

Wiring Modification 1975-1978 Model Year Vehicles

Fan Switch Plug Wire Placement:

1. Connect wires into the fan switch plug according to marks placed on switch connector, refer to above image.

2. Connect black blower motor ground wire to blower housing to trans tunnel (floor) bracket.

Fan Switch Plug:

3. Join blower motor connectors (arrow).

Modified Blower Motor Wiring Diagram:

4. Install the yellow wire which was previously located in pin #3 of the old fan switch plug into pin #6 of the new switch plug. Refer to schematic.

5. The opposite end of the yellow wire is connected to fuse #2. Refer to schematic.

6. Use a new wire and connect it from pin #5 on the fan switch plug to terminal #87 on the AC-relay. Refer to schematic.

7. Use a new wire and connect it from fuse #3 to terminal #86 on the AC-relay. Refer to schematic.

Fan Switch Plug:

8. Connect the connector to the switch.

9. Fit the switch to the central console.

10. Fit the switch knob.

11. Connect battery ground cable.

12. Test the operation of the new blower motor.

13. Reassemble/install remaining dash components in the reverse order of disassembly/removal.

Wiring Modification 1979 Model Year Vehicles

Fan Switch Plug Wire Placement:

Fan Switch Plug:

3. Join blower motor connectors (arrow).

Modified Blower Motor Wiring Diagram:

4. Install the white-black wire which was previously located in pin #3 of the old fan switch plug into pin #6 of the new switch plug. Refer to schematic.

5. The opposite end of the white-black wire is connected to fuse #3. Refer to schematic.

6. Use a new wire and connect it to pin #5 on the fan switch plug to the switched side of the thermostat switch. Refer to schematic.

^ To determine which wire is the switched side of the thermostat, disconnect both wires and start the engine. Wait 15 seconds. Using a test light determine which side is the hot side.

7. Connect the new wire, from pin #5 of fan switch connector, to the green thermostat switched wire. Refer to schematic.

8. Reconnect the combined new wire and switched green wire to the thermostat. Refer to schematic.

9. Take the white wire from terminal #86 on the AC-relay and connect it to the white-black wire now in pin #6 of the fan switch plug. Refer to schematic.

Fan Switch Plug:

10. Connect the connector to the switch.

11. Fit the switch to the central console.

12. Fit the switch knob.

13. Connect battery ground cable.

14. Test the operation of the new blower motor.

15. Reassemble/install remaining dash components in the reverse order of disassembly/removal.

Wiring Modification 1980 Model Year Vehicles

Fan Switch Plug Wire Placement:

Fan Switch Plug:

3. Join blower motor connectors (arrow).

Modified Blower Motor Wiring Diagram:

Fan Switch Plug:

Fan Switch Plug Wire Placement:

Fan Switch Plug:

3. Join blower motor connectors (arrow).