Testing a Solenoid Valve To test the solenoid valve in an individual strut, perform the following steps: • turn the ignition switch to OFF, • connect a fused jumper wire between a known good ground and the strut solenoid’s terminal in the control unit connector (back-probe connector at the control unit, do not disconnect) • connect a fused jumper wire between a known good ground and the air charge solenoid’s terminal in the control unit connector (back-probe connector at the control unit, do not disconnect), • turn ignition switch to ON.
The strut should now begin to raise with pressure from the tank. When tank pressure drops to 109 psi, the pressure switch should close, and the control unit should turn on the compressor. If either solenoid fails to energize, make sure your connections are good, then check the solenoid with a multimeter. Compressor Does Not Run
If the compressor fails to run during any strut-inflation checks, the pressure switch may be faulty. The following paragraphs describe several checks you can make. You can bypass the pressure switch to see if that causes the control unit to turn the compressor on. To do that, separate the connector from the pressure switch. On the harness side, connect a jumper between the two terminals.

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