Vacuum Pump: Testing and Inspection

Fig. 53 Speed Control Vacuum Pump Inspection:

1. Disconnect electrical connector from vacuum pump assembly, then measure resistance between terminal one and two and terminals one and three, resistance should be between 50-60 ohms.
2. Apply battery voltage between terminal one and two and terminals one and three, ensure operating sounds of solenoid valves are heard.
3. If solenoid valves are defective, replace vacuum pump assembly.
4. Check motor by applying battery voltage across terminals one and four, ensure motor operates, if not replace motor.