GM Prizm/Nova 1985-1993 Repair Guide

Brake Light Switch

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The brake light switch is located at the top of the pedal arm. It is the switch which turns the brake lights on when the brakes are applied. The plunger type switch is held in the off position by the normal position of the brake pedal; when the pedal moves during brake application, the switch plunger moves forward and the brake lights are brought on.

The switch is almost always the first place to look for the cause of the brake lights flickering over bumps or staying on without use of the brakes. If the brake lights fail to work with the brakes applied, check the fuse first and then check the switch.

REMOVAL & INSTALLATION



1985-92

See Figure 1

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the wiring from the switch terminals. Put a piece of tape over each exposed wiring connector; 1 wire terminal may be hot even though the ignition is off. If it accidentally touches metal, a fuse will blow.
  4.  

On Novas, it may be necessary to remove the lower dash trim panel and air duct for access.

  1. Loosen the locknut closest to the brake pedal arm. Unscrew the switch from the nut and remove it from the bracket.
  2.  

To install:
  1. Install the new switch and tighten the retaining nuts finger tight when the switch plunger is lightly compressed against the stopper on the pedal.
  2.  
  3. Connect an ohmmeter across the terminals of the switch. Move the brake pedal and check the on-off behavior of the switch. Adjust the switch so that the switch comes on at the bottom of the pedal free-play. This brings the brake lights on just as the brakes apply but no sooner.
  4.  
  5. Tighten the locknuts to hold the switch in position.
  6.  
  7. Remove the tape and connect the wiring to the switch.
  8.  



Click image to see an enlarged view

Fig. Fig. 1: Brake light switch - 1985-92

1993

See Figure 2

  1. Disconnect the negative battery cable.
  2.  
  3. Slide the hood latch release cable sideways to release from the holder.
  4.  
  5. Disconnect the hood release cable from the hood latch release lever.
  6.  
  7. Remove the hood latch release lever from the knee bolster by removing the 2 retaining screws.
  8.  
  9. Remove the knee bolster from the instrument panel by removing the 2 cover plates, 2 screws, and four bolts.
  10.  
  11. Disconnect the left side ventilation duct from the left side duct outlet.
  12.  
  13. Disconnect the stoplamp switch electrical connector from the switch.
  14.  
  15. Loosen the stoplamp switch locknut and loosen the pushrod locknut and remove the switch.
  16.  

To install:
  1. Adjust the pedal height by turning the pushrod until the brake pedal height is within specification and tighten the pushrod locknut to 18 ft. lbs. (25 Nm). Refer the Pedal Height procedure earlier in the Section.
  2.  
  3. Adjust the stoplamp switch by turning it until the distance between the end of the stoplamp switch plunger and the end of the threaded portion of the switch is 0.02-0.09 inch (0.5-2.4 mm). Tighten the stoplamp switch locknut to 89 inch lbs. (10 Nm).
  4.  
  5. Connect the stoplamp switch electrical connector to the switch.
  6.  
  7. Connect the left side ventilation to the left side duct outlet.
  8.  
  9. Install the knee bolster to the instrument panel with the 2 screws and four bolts.
  10.  
  11. Install the 2 cover plates.
  12.  
  13. Install the hood latch release lever to the knee bolster with the 2 retaining screws.
  14.  
  15. Connect the hood release cable to the hood latch release lever.
  16.  
  17. Slide the hood latch release cable into the holder.
  18.  
  19. Connect the negative battery cable.
  20.  



Click image to see an enlarged view

Fig. Fig. 2: Brake light switch clearance - 1993

 
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