1979 Models (3-Way Solenoid Test)
- Remove vacuum sensing tube from servo diaphragm. Remove intake manifold vacuum tube from 3-way solenoid. Detach wire from 3-way solenoid which comes from engine speed switch. Ground 3-way solenoid at disconnected terminal using jumper wire.
- Turn ignition on (engine off). Blow air through vacuum hose disconnected from servo diaphragm and note that air should come out of 3-way solenoid filter (cap can be removed for easier checking). See Figure.
- Turn ignition off. Blow air into same vacuum tube and note that air should now come from nipple which normally connects to intake manifold. If valve does not function in this manner, replace 3-way solenoid.