Chevrolet Full Size Cars 1979-1989

Brake Release Switch


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Fig. Fig. 1 Examples of clip mounted cruise control release switches

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Fig. Fig. 2 View of a late model, clip-mounted, electric cruise control/brake switch

All factory or dealer installed cruise control systems for these vehicles are equipped with either a brake or clutch release switch. The purpose of the switch is to deactivate the system when the driver begins to depress the pedal. Most of these switches found on earlier models are vacuum break switches which will therefore have a vacuum line attached to the rear of the switch. On later vehicles, many of the switches are electric and may even be combined with other switches (such as the brake light switch).

The switches are mounted using one of two possible methods. Some earlier switches are mounted using a locknut. Later switches are normally mounted using an interference clip which holds ribs on the switches neck.


  1. If equipped with an electric switch, disconnect the negative battery cable.
  3. Disengage the vacuum line or the electrical connector(s) from the switch.
  5. For locknut mounted switches, loosen and remove the locknut, then withdraw the switch from the pedal bracket.
  7. For interference fit switches, grasp the switch and withdraw it from the clip. If necessary the clip can be removed from the pedal bracket as well. Some clips are designed with lock tangs and may be pivoted in order to pull them from the bracket. Other clips are also an interference fit and must be squeezed and withdrawn. To install:
  9. Install the switch and locknut or clip, as applicable to the pedal bracket.
  11. Adjust the switch plunger height to assure proper operation.
  13. Engage the vacuum line or electrical connector(s) to the switch.
  15. If removed, connect the negative battery cable.
  17. Verify proper switch operation.


Locknut Mounted Switch

Locknut mounted switches are adjusted by correctly positioning the switch in the pedal bracket, then holding the switch in position while tightening the locknut. To position the switch, insert it into the pedal bracket so the plunger is fully depressed when the pedal is released, but is at full travel (all of the way out) once the pedal is depressed approximately 1 / 4 in. (6.35mm) for electric switches or 5 / 16 in. (7.94mm) for vacuum switches.

Clip Mounted Switch

Clip mounted switches are automatically adjusted during installation. The clip holds the switch in position by the raised ribs located on the switche's neck. In order to adjust the switch, first fully seat it into the clip and against the pedal bracket. Grasp the pedal and pull it fully back against the stop. While pulling the pedal backwards, a clicking sound should be heard as the switch is pushed backwards in the clip unit it is in the proper position. Make sure the switch plunger is seated when the pedal is released and that the plunger fully extends as the pedal is depressed. Check the switch operation and adjust again, if necessary.