Test 18, A/C Pressure Switch Operation Check

With engine at idle, A/C and blower on, measure voltage at A/C pressure switch terminals while observing A/C compressor clutch cycling. A/C pressure switch is functioning properly if:

• When A/C compressor clutch is off, Blue/Green wire has 0-4 volts and Blue/Black wire has 10-14 volts.
• When A/C compressor clutch is on, Blue/Green wire has 0-4 volts and Blue/Black wire has 0-4 volts.

  If switch is functioning properly, go to TEST 22. If switch is not functioning properly, replace A/C pressure switch.