Circuit Description
WARNING: This page is about a different car, the 1995 Oldsmobile Ninety-Eight and 1995 Buick Park Avenue. However, it is still accessible from the selected car via links, so may be relevant.
Cruise switch within turn signal lever receives ignition voltage from a 15-amp fuse to turn signal lever cruise switches. Cruise ON/OFF, SET/COAST and RESUME/ACCEL switches are inputs to cruise portion of PCM.
Cruise servo vent and vacuum solenoids output are controlled by high side drivers in PCM. When ignition is on, PCM looks at these output lines and will set codes if an incorrect status is seen on any line.
Vent solenoid is a normally-open (de-energized) solenoid valve that allows vacuum in cruise servo to be depleted. When solenoid is on (energized), cruise servo holds vacuum allowing servo to remain retracted and hold throttle open.