Refrigerant Pressure Sensor / Switch: Testing and Inspection

A/C Pressure Switch -F129-

Checking
- Start engine.
- Switch compressor on (select AUTO mode).

If the compressor is activated:







- Disconnect harness connector -B- from switch.
- A/C Compressor will stop (low pressure switch open).
- Remove switch -A- and install harness connector -B-.
A/C Compressor will not be activated (low pressure switch open).

If the compressor is not activated:
- Disconnect harness connector -B- from switch -A- and bridge terminals -1- and -2- on harness connector -B-.
The compressor will be activated.

NOTE:
- If the compressor is activated when the terminals are connected together, refrigerant system pressure is low or system is empty (check refrigerant system pressures), or the switch is malfunctioning. A/C Refrigerant System Pressures, Checking
- If the compressor is not activated and the measuring value block display indicates A/C pressure switch -F129- as the cut-off condition, there is an open circuit in the wiring between A/C pressure switch - F129- and A/C control head -E87-. Trace and repair open circuit after performing electrical test. Component Tests and General Diagnostics