Electrical & Vacuum Release Switches

1987 Chevrolet Hi-Cube 6.2 J, 475/M40SECTION Electrical & Vacuum Release Switches

These switches are used to disengage cruise control whenever clutch or brake pedals are activated. An electrical release switch is mounted on brake and clutch pedal (M/T) brackets. Switches disengage system electrically if either pedal is depressed. See Fig 1 .

A vacuum release valve is also mounted on brake pedal bracket. This valve vents trapped vacuum in servo to atmosphere as brake pedal is depressed, allowing throttle to quickly return to idle position. This is done by routing a separate hose directly to servo from normally closed vacuum switch. See Fig 1 .

Fig 1: Vacuum Release Valve
G17052Courtesy of GENERAL MOTORS CORP.
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