GM Astro/Safari 1985-1996 Repair Guide

Neutral Safety Switch

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On 1985-95 vehicles covered by this guide, the Neutral Safety Switch is a part of the Back-Up Light Switch and is mounted to the steering column. For replacement or adjustment, please refer to the Back-Up Light Switch, Removal and Installation procedures in Chassis Electrical of this guide.

In 1996, the neutral safety switch was relocated to the side of the transmission assembly. This change corresponds to the change made that year from shift linkage to a shift cable.

REPLACEMENT & ADJUSTMENT



See Figures 1 and 2



Click image to see an enlarged view

Fig. Fig. 1: Exploded view of the transmission mounted neutral safety switch-1996 models only



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Fig. Fig. 2: Use the adjustment tool to greatly ease your job during neutral safety switch adjustment or installation

Any removal of the switch will require that the switch is adjusted before installation. Switch adjustment should only be accomplished using J-41364-A or an equivalent switch adjustment and alignment tool. If the tool is not available, you may be able to successfully adjust the switch using a hit and miss method, moving the switch slightly each time and rechecking to verify that the switch works properly (the vehicle starts ONLY when the transmission is in Park or Neutral). But, this could take some time and be quite frustrating, so an attempt to buy or borrow the adjustment tool first may be well worth it.

  1. Firmly apply the parking brake and block the rear wheels.
  2.  
  3. Disconnect the negative battery cable for safety.
  4.  
  5. Shift the transmission into Neutral.
  6.  
  7. Raise and support the front of the vehicle safely using jackstands.
  8.  
  9. Before attempting to remove or adjust the switch, make sure that the transmission is in the mechanical Neutral position. You can verify this at the control lever on the transmission assembly by rotating it clockwise until it reaches the FULL STOP position, then rotating it back counterclockwise 2 detents.
  10.  
  11. Disconnect the shift cable end from the transmission shift control lever by pulling the cable end from the lever ball stud.
  12.  
  13. Remove the nut securing the control lever to the manual shaft.
  14.  
  15. Disengage the wiring connectors from the neutral safety/back-up light switch.
  16.  
  17. Remove the 2 bolts which secure the switch to the transmission assembly.
  18.  
  19. Slide the switch from the manual shaft. If there is difficulty removing the switch, file the outer edge of the manual shaft lightly to remove any burrs from the shaft.
  20.  

To adjust:
  1. Position J-41364-A, or an equivalent adjustment tool, onto the neutral safety switch, making sure that the 2 slots on the switch (located where the manual shaft is inserted) are aligned with the 2 lower tabs on the tool. Then, rotate the tool until the tool's upper locator pin is aligned with the slot on the top of the switch.
  2.  

During installation, leave the adjustment tool mounted to the switch until the switch is secured and the position cannot change.

To install:
  1. Check the outer edge of the manual shaft to make sure there are no burrs which could prevent switch installation. If necessary, file the edge lightly to remove any remaining burrs.
  2.  
  3. Align the switch hub flats with the flats on the manual shaft.
  4.  
  5. Slide the switch onto the transmission manual shaft until the switch mounting bracket contacts the mounting bosses on the transmission.
  6.  
  7. Secure the switch to the transmission using the 2 retaining bolts. Tighten the bolts to 21 ft. lbs. (28 Nm).
  8.  
  9. Remove the switch adjustment tool from the switch assembly.
  10.  
  11. Engage the wiring harness connectors to the switch.
  12.  
  13. Install the transmission control lever to the manual shaft, then secure using the retaining nut. Tighten the nut to 21 ft. lbs. (28 Nm).
  14.  
  15. Connect the negative battery cable, then verify proper switch operation. The engine MUST start ONLY with the transmission in Park or Neutral. If further adjustment is required, loosen the switch retaining bolts and rotate the switch slightly, then tighten the bolts and check for proper operation.
  16.  
  17. Remove the jackstands and carefully lower the vehicle.
  18.  

 
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