Air Suspension Testing without FordStar Tester

Quick Checks Without New Generation Star Tester

NOTE: The following measurements and tests are general system checks. Only use these checks if the recommended pinpoint tests have not resolved the concern or if there is not a New Generation Star tester available.

NOTE: These checks are not provided as a substitute for proper procedures.

1. Turn air suspension switch ON.

2. Disconnect control module black connector.

3. Disconnect control module gray connector.  
   
   

   Expected Voltage and Resistance Readings

   Circuit Function	Pin Numbers	Meter Reading
   Control Module Ground	Pin C205-32 to battery ground terminal	Less than 1 ohm resistance. NOTE: There must be a good ground before additional measurements are made.
   Control Module Power	Pin C204-1 (+) to Pin C205-32 Pin C204-21 (+) to Pin C205-32	B+ B+
   Ignition Signal	Pin C204-4 (+) to Pin C205-32	Ignition switch OFF=0 volts Ignition switch in RUN=B+
   Courtesy Lamp Switch Signal	Pin C204-5 (+) to Pin C205-32	Both doors closed=0 volts Either door open=B+
   Star Tester Input (STI) Line	Pin C204-6 (+) to Pin C205-32	Voltage=0 volts Resistance=greater than 1000 ohms
   Air Suspension Switch	Pin C205-11 (+) to Pin C205-32	Switch OFF=B+ Switch ON=0 volts
   Star Tester Output (STO) Line	Pin C205-12 (+) to Pin C205-32	Ignition OFF=0 volts Ignition in RUN=6.0 volts
   Spring Solenoid Valves	Pin C205-14 to Pin C205-32  LH front  Pin C205-15 to Pin C205-32  RH front  Pin C205-16 to Pin C205-32  LH rear  Pin C205-17 to Pin C205-32  RH rear	Resistance=14 to 18 ohms, nominal 16 ohms
   Compressor Relay Control Line	Pin C205-18 (+) to Pin C205-32	B+
   Vent Solenoid	Pin C205-30 to Pin C205-32	Resistance=19 to 24 ohms, nominal 21 ohms

4. If the measurements of voltages and resistance have fallen within the given limits, the system output may now be tested. If the voltages and resistance are not within limits, service the faults before continuing.

5. The following tests are done with the control module black and gray connectors C204 and C205 disconnected.

6. Use a jumper with an in-line fuse rated at not more than 5 amps.  
   
   

   Solenoid and Relay Output Circuit Checks

   Action	Expected Result
   Connect the jumper between the battery supply pin, Pin C204-1 and the individual solenoid pins: LH front, Pin C205-14  RH front, Pin C205-15  LH rear, Pin C205-16  RH rear, Pin C205-17  Vent solenoid, Pin C205-30	Each solenoid will click open as power is applied and should click closed as power is removed. A second person listening at the solenoid locations is necessary.
   Connect the jumper between the ground pin, Pin C205-32, and the compressor relay control line at Pin C205-18.	The air suspension system compressor will begin running when ground is applied to Pin 18 and stop running when the ground is removed.

7. After all of the system measurements and the test previously listed have been completed, perform the following measurements.

8. Perform the following measurements with the control module connectors connected to the control module. The air suspension switch must be ON and the ignition switch must also be in RUN.

9. The following measurements are made by backprobing the control module connectors. Use care to see that the wires are not damaged and that the insulation is not cut.  
   
   

   Height Sensor Voltage Reading

   Circuit Description	Pin Numbers Wire Colors	Meter Reading (Voltage)
   Air Suspension Height Sensor Power	Pin C205-28 (+) PK/W and Pin C204-10 (-) BK/PK	Approximately 5.0 volts
   Air Suspension Height Sensor Signal	Left front: Pin C204-7 (+) PK/BK to Pin C204-10 (-) BK/PK Right front: Pin C204-8 (+) T to Pin C204-10 (-) BK/PK Left rear: Pin C204-9 (+) O/BK to Pin C204-10 (-) BK/PK	Maximum: Approximately 4.5 volts Minimum: Approximately 0.5 volt Voltage should be at Approximately 2.5 volts with vehicle at normal ride height. Voltage should fluctuate as corners are bounced.