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Blower Motor Testing

WARNING: To avoid accidental air bag deployment, see AIR BAG DEACTIVATION SERVICING PRECAUTIONS in this article.
  1. Blower motor and heater share a common circuit breaker in the fuse box. See Fig 1 . Check heater circuit breaker. If circuit breaker Red button is in (depressed), go to step 2). If Red button is out (not depressed), check for short circuit in harness. Repair harness as necessary. Depress Red button to reset circuit breaker.
    Fig 1: Identifying Blower Fuse Positions
    G90D04523Courtesy of MAZDA MOTORS CORP.
  2. Check fuse. On non-turbo manual transmission models, the blower and windshield wipers share a common 15-amp fuse, located in fuse box. On all other models, blower motor and instrument gauges share a 10-amp fuse located in fuse box. See Fig 1 . Go to step 3) if fuse is okay. If fuse is not okay, check for short circuit in harness. Repair harness as necessary before replacing fuse.
  3. Turn ignition on. Turn blower switch to maximum position. Measure voltage at terminals of blower motor connector. See Fig 2 . See BLOWER MOTOR VOLTAGE TEST  table.
    BLOWER MOTOR VOLTAGE TEST

    Terminal Voltage Action To Take
    Blue/White 12 Check Black Wire
    Blue/White 0 Go To Step 4)
    Black 12 Repair Wiring Harness Between Blower Motor And Body Ground
    Black 0 Replace Blower Motor
    Fig 2: Identifying Blower Motor Test Terminals
    G90F04524Courtesy of MAZDA MOTORS CORP.
  4. Turn ignition and blower switches on. Measure voltage at terminals of heater relay connector. See Fig 3 . See HEATER RELAY VOLTAGE TEST table.
    Fig 3: Identifying Heater Relay Test Terminals
    G90I04525Courtesy of MAZDA MOTORS CORP.
    HEATER RELAY VOLTAGE TEST

    Wire Voltage Action to Take
    Red/Yellow 12 Go to Step 5
    Red/Yellow 0 Check Blue Wire
    Blue 12 Check Lt. Green/Black Wire
    Blue 0 Repair Wiring Harness Between Circuit Breaker And Heater Relay
    Lt. Green/Black 12 Check Blue/White Wire
    Lt. Green/Black Below 2 (1)
    Blue/White 12 Go to step 10)
    Blue/White Below 2 Replace Heater Relay
    (1) On non-turbo manual transmission models, repair wiring harness or circuit breaker to heater relay. On all other manual transmission models, go to step 9).
  5. Turn ignition switch and blower switch on. Measure voltage at Blue/Orange wire of logicon switch assembly connector while moving blower switch from low to maximum. See Fig 4 . If voltage is 5-12 volts, go to step 6). If no voltage is present, check fan amplifier. See FAN AMPLIFIER  under TESTING.
    Fig 4: Measuring Logicon Blue/Orange Wire Voltage
    G90A04526Courtesy of MAZDA MOTORS CORP.
  6. Check for continuity between Red/Yellow wire of heater relay connector and Red/Yellow wire of power transistor connector. See Fig 5 . If continuity is present, go to step 7). If continuity does not exist, repair wiring harness.
    Fig 5: Checking Continuity Between Heater Relay & Power Transistor
    G90C04527Courtesy of MAZDA MOTORS CORP.
  7. Check for continuity between Blue/Orange wire of logicon switch assembly connector and Blue/Orange wire of the power transistor connector. See Fig 6 . If continuity is present, go to step 8). If continuity does not exist, replace power transistor.
    Fig 6: Continuity Between Logicon Switch Assembly & Power Transistor
    G90E04528Courtesy of MAZDA MOTORS CORP.
  8. Check for continuity between Blue/White wire of blower motor connector and Blue/White wire of power transistor connector. See Fig 7 . If continuity is present, replace power transistor. If not, repair wiring harness.
    Fig 7: Checking Continuity Between Blower Motor & Power Transistor
    G90G04529Courtesy of MAZDA MOTORS CORP.
  9. Turn ignition switch and blower switch on. Measure voltage at wires of ignition relay connector. See Fig 8 . See IGNITION RELAY VOLTAGE TEST table.
    IGNITION RELAY VOLTAGE TEST

    Wire Voltage Action To Take
    Yellow 12 Check Wire Yellow/Blue
    Yellow 0 Repair Wiring Harness Between Meters Fuse And Ignition Relay
    Yellow/Blue 12 Repair Wiring Harness Between Ignition Relay And Starter Motor
    Yellow/Blue 0 Check Yellow/White wire
    Yellow/White 12 Check Light Green/Blue Wire
    Yellow/White 0 Repair Wiring Harness Between Meters Fuse And Ignition Relay
    Lt. Green/Black 12 Repair Wiring Harness Between Ignition Relay And Heater Relay
    Lt. Green/Black Below 2 Replace Ignition Relay
    Fig 8: Ignition Relay Terminal Wires
    G90I04530Courtesy of MAZDA MOTORS CORP.
  10. Turn ignition and blower switch on. Measure voltage at Green/Red wire of logicon switch assembly connector. See Fig 4 . If 12 volts is present, check fan amplifier. If less than 2 volts is present, repair wiring harness between heater relay and logicon switch assembly.
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