Vacuum Switch
- Run the engine at idle. Connect a voltmeter to the vacuum switch connector Green terminal. Voltmeter should read below 1.5V. Disconnect and plug vacuum sensing tube from the vacuum switch. Voltmeter should read 12V. See Fig 1 .
- The vacuum switch may be tested off the vehicle. Connect a vacuum pump and a circuit tester to the switch. At atmospheric pressure, there should be no continuity between the switch terminals. Switch should show continuity at 2.36 in. Hg or below.