Checking the expansion valve on a car
1. Install the gauge block.
2. Check the operation of the expansion valve.
A) Start the engine and set the idle speed to high. Turn on the air conditioner.
b) Check that the low pressure gauge reading is between 49 - 490 kPa (5 -5.0 kg/cm2).
If pressure is low, check and replace expansion valve and/or receiver.
If pressure is higher, tighten valve connections and/or replace expansion valve.
Removing
1. Disconnect the negative lead from the battery.
2. Remove the refrigerant from the system.
3. Disconnect the suction hose from the outlet fitting of the cooling unit.
4. Disconnect the liquid tube from the inlet fitting of the cooling unit.
Note: Plug the open ends of the tubes immediately.
5. Remove gaskets from inlet and outlet fittings.
6. Remove the glove box and air duct.
7. Disconnect the temperature control button connectors and wire harness connector.
8. Remove the cooling unit by removing two nuts and four screws and one bolt.
9. Disconnect the A/C harness from the cooling unit.
Evaporator check
1. Check the evaporator plates.
If the plates are clogged, blow them out with compressed air.
Note: never rinse the evaporator with water!
Straighten bent plates.
Checking the Thermistor
1. Place the thermistor in cold water. When the water temperature changes, measure the thermistor resistance at the same time as measuring the water temperature.
2. Compare the results with the graph. If the result does not fall within the area between the lines, the thermistor should be replaced.