Mazda RX7 Engine Cooling Fans: coolant temperature, thermosensor and more

Mazda RX7 1993-1995 FD3S

COMPONENT TESTING

Cooling Fan Motor (2-Speed Or 3-Speed)

1. Ensure battery is fully charged. Disconnect cooling fan motor connector. Connect ammeter between battery and cooling fan motor connector for desired fan speed test.
See Fig. 1.
2. Ensure cooling fan motor operates smoothly on all speeds at specified current. If cooling fan motor draws more or less than specified amperage, check wiring. If wiring is okay, replace cooling fan motor.

Fig. 1: Testing Cooling Fan Motor (RX7)

COOLING FAN MOTOR CURRENT SPECIFICATIONS

• Mazda RX7 1993-1995
  • Low Speed: 5.8-11.8
  • Medium Speed: 6.5-12.5
  • High Speed: 10.6-16.6

Coolant Temperature Sensor (CTS)

Disconnect negative battery cable. Remove coolant temperature sensor. Suspend coolant temperature sensor in a container filled with water. Place a thermometer in container. Connect ohmmeter between coolant temperature sensor connector terminals. See Fig. 2 . Gradually heat water and measure Coolant Temperature Sensor (CTS) resistance. If resistance is not as specified, replace coolant temperature sensor.

Fig. 2: Testing CTS




CTS RESISTANCE SPECIFICATIONS

• Mazda RX7 1993-1995
  • 68°F (20°C): 2.20-2.70k Ohms
  • 176°F (80°C): 0.29-0.35k Ohms

Coolant Thermosensor (RX7)

Disconnect negative battery cable. Remove coolant thermosensor. Suspend coolant thermosensor in a container filled with water. Place a thermometer in container. Connect ohmmeter between coolant thermosensor terminal and base. Gradually heat water and check sensor resistance. If resistance is not as specified, replace coolant thermosensor.

COOLANT THERMOSENSOR RESISTANCE SPECIFICATIONS

• Coolant Temperature
  • 214°F (101°C): 0.5 (Maximum) Ohms
  • 226°F (108°C): 1.0 (Minimum) Ohms

Cooling Fan Relays (RX7)

1. Locate cooling fan relays in relay block on right inner fender panel. See Fig. 3 . Disconnect cooling fan relay wiring harness connector. Check continuity between cooling fan relay terminals "A" and "B". See Fig. 3 . Continuity should exist. Check continuity between terminals "C" and "D". Continuity should not exist.
2. With battery voltage applied between terminals "A" and "B" of cooling fan relay, check continuity between terminals "C" and "D". Continuity should exist. If continuity is not as specified, replace cooling fan relay(s).

Fig. 3: Testing Cooling Fan Relays (RX7)



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Mazda RX-7 1993-1995 FD3S

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