Barometric Pressure Switch: Testing and Inspection
Fig. 11 Checking vacuum switch.:
Fig. 14 Vacuum specs., vacuum switch.:
1. Remove vacuum switch from vehicle.
2. Connect a hand vacuum pump to vacuum switch and check continuity across switch terminals using an ohmmeter Fig. 11.. Continuity should exist with more than 4.7 inches Hg vacuum applied and should not exist with less than 4.7 inches Hg vacuum applied to switch Fig. 14..
3. Replace vacuum switch if operation is not as described.