Compressor/Pump: Testing and Inspection

NOTE: This test can be performed on the vehicle to evaluate compressor current draw, pressure output and leak down.

To test compressor performance, proceed as follows:
1. Disconnect compressor motor wiring harness.
2. Disconnect air line between dryer and strut or spring solenoid.
3. Connect a suitable air pressure gauge into the Automatic Air Suspension (AAS) system. Refer to RESIDUAL AIR CHECK.

Fig. 45 Compressor Current Draw Test:

4. Connect a suitable ammeter in series between compressor connector red wire terminal and a 12 volt power source. Also connect a ground wire from compressor connector black terminal to a known good ground on frame.
5. If compressor motor current draw exceeds 30 amps, replace compressor assembly.