Disassembly of the heater electric fan unit.
1 - upper part of the evaporator housing, 2 - upper part of the evaporator housing, 3 - resistor (manual air conditioner) or power transistor (automatic air conditioner), 4 - evaporator tube mounting bracket, 5 - intake air damper, 6 - intake air damper lever, 7 - damper "A" intake duct, 8 - damper lever "A" intake duct, 9 - lever (big) intake duct damper, 10 - spring washer, 11 - air intake mode selector damper servomotor, 12 - intake duct housing seal, 13 - evaporator, 14 - thermal switch (thermistor), 15 - O-ring, 16 - evaporator tube cover, 17 - evaporator housing lower part, 18 - evaporator housing lower part, 19 - heater motor and impeller assembly, 20 - heater electric fan cooling tube, 21 - bracket, 22 - retainer, 23 - seal, 24 - cabin filter, 25 - cabin filter cover, 26 - seal, 27 - seal, 28 - gasket, 29 - power relay (automatic air conditioner).
Note: the removal of the cabin filter is given in the chapter "Maintenance and general inspection and adjustment procedures".
Disassembly and assembly
1. When removing parts, refer to the figure "Dismantling the block of the electrofan of a heater".
2. Installation is made in an order, the return to removal.
Checking the thermal switch (thermistor)
1. Thermal switch (thermistor) determines the temperature of the evaporator. A sensor signal cuts off power to the compressor magnetic clutch relay to prevent freezing of the evaporator due to excessive cooling.
2. Checking the thermal switch.
- A) Remove the glove box.
- b) Start the engine.
- V) Turn on the air conditioner.
- G) Using a multimeter, measure the voltage between the terminals "2" And "3" thermistor and check its operation.
- Rated voltage: 12V
Trigger conditions:
- OFF→ON: 4.3±1.0°C
- ON→OFF: 1.5±0.5°C
Checking the evaporator air temperature sensor (automatic air conditioner)
1. The evaporator air temperature sensor is mounted on the evaporator shell.
2. The sensor determines the air temperature in the evaporator and sends a corresponding signal to the air conditioning control unit.
3. Sensor check.
- A) Remove the evaporator.
- b) Remove the evaporator air temperature sensor.
- V) Measure the resistance between the sensor leads at the following temperatures and verify that the resistance is within the rated value.
Rated value:
- at an air temperature of 0°C: 11.1-11.6 kOhm
- at an air temperature of 15°C: 5.8-6.1 kOhm
Checking the heater fan motor
1. Connect the power (battery voltage) to the motor terminals and check that the fan is rotating.
2. Reverse the connection polarity and check that the motor rotates in the opposite direction.
Checking the heater fan motor resistor (manual air conditioner)
Measure the resistance between the terminals of the resistor connector. If the resistance is out of specification, replace the resistor.
Table. Rated values.
Switch position | Chain (conclusions) | Resistance, Ohm |
LO | 4 ↔ 3 | 2,9±5% |
ML | 4 ↔ 1 | 1,2±0,12% |
MN | 4 ↔ 2 | 0,4±0,04% |
Check of the relay of the electric motor of the fan of a heater
1. Make sure there is continuity between the terminals "1" ↔ "3", when the air conditioner is on.
2. Make sure there is continuity between the terminals "4" ↔ "5" when voltage is applied from the battery to the terminals "1" And "3".