Compressor Will Not Operate
NOTE:
Compressor has a temperature override circuit breaker built-in to stop unit if overheating occurs. As compressor cools, circuit breaker will automatically reset itself and compressor operation will resume.
- Test system for faulty compressor, pressure switch, control unit or defective electrical circuit. If vehicle height is abnormal, See VEHICLE RISES ABNORMALLY test. If height is normal, disconnect pressure switch and short-circuit terminal on connector side. See Fig 1 .
- If compressor runs, allow to operate for 3 minutes and place control switch in "HI" position. If vehicle responds to control box command, replace pressure switch. See Figure . If not, air charge valve or wire circuit are defective.
- If compressor does not operate with pressure switch short-circuited, disconnect control unit wire harness connector. Use voltmeter to measure current at harness connector terminal No. 33 and ground. See Fig 2 .
- If 1.5 volts does not appear, repair wiring between pressure switch or control unit and ground. With 1.5 volts at terminal No. 33, check voltage between control unit terminal No. 12 and ground. If 1.5 volts does not appear, replace control unit. If 1.5 volts is present, proceed to step 5).
- Test compressor relay by applying 12 volts to terminal "B" and ground terminal "A". Verify that continuity exists between terminals "C" and "D". See Figure . Remove voltage from terminal "B" and confirm continuity is no longer present at terminals "C" and "D". Replace relay if necessary.
- Carefully inspect wiring system for wear, defects or disconnected leads. Test compressor by applying 12 volts directly to unit. Replace compressor if necessary.