General testing condition:

Blower motor runs at all 3 speeds. Both vacuum units disconnected. Heater off.

Compressor V-belt tight.

All duct gaskets must be air tight (otherwise eva porator would ice up). Condenser clean.


For initial testing place hand on service valves of compressor with air conditioner switched on. After compressor has run just a short time, low pressure valve (suction side) must be cold and high pressure valve (discharge side) warm.


Connect high- and low- pressure gages. Adjust engine speed to about 2500 rpm. Insert thermometer in center outlet. Set air conditioner at maximum cooling. Shut car doors and windows.

No cooling at all

Safety seal ruptured?

(Safety seal will have a hole when fuse insert is ruptured)

System has been overheated. Check direction of rotation of radiator and condenser fans. If condenser fan does not turn, replace relay or air conditioner switch.

Did compressor clutch engage?

Note pressure readings

Measure voltage against ground at plug in supply line to compressor clutch.


1. Low pressure side reads low. High pressure side reads low. Discharge air temperature in center outlet: approx. ambient temperature.

No refrigerant in system. Charge air conditioner. Find leak and eliminate.

2. Low pressure side reads high. High pressure side reads low. Discharge air temperature: approx. ambient temperature.

Compressor is defective.

3. Low pressure side reads high . High pressure side reads high. Discharge air temperature: approx. ambient temperature.

Expansion valve is defective.

Achtung! Schutzbrille tragen

Bel leerem FOIIzfllnder Heining ^^ nicht einschalten__

0 0

Post a comment