GM S-Series Pick-ups and SUV's 1994-1999 Repair Guide

Back-Up Light/Neutral Safety Switch

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REMOVAL & INSTALLATION



Automatic Transmission

See Figure 1



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Fig. Fig. 1: The neutral safety switch is located on the side of the transmission

The back-up light switch on automatic transmission vehicles also acts as the neutral safety switch. The switch will activate the reverse lights when the gear shift lever is placed in the Reverse position, and it will prevent the engine from starting unless the shifter is in Neutral or Park. The switch on 1994 models is mounted to the steering column. Refer to Drive Train of this repair guide for column mounted switch removal. On 1995 and later models, the switch is mounted on the transmission.

  1. Apply the parking brake and place the transmission in Neutral .
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Raise the vehicle and support it with jackstands.
  6.  
  7. Remove the transmission control lever-to-manual shaft nut and disconnect the control lever from the manual shaft. Let the cable and control lever drop out of the way.
  8.  
  9. Unplug the switch electrical connection.
  10.  
  11. Unfasten the switch retainers and slide the switch off the shaft to remove it from the vehicle.
  12.  

To install:
  1. Install neutral safety switch alignment tool J 1364 or its equivalent onto the switch. Make sure that the two detents on the switch (where the manual shaft is inserted) are lined up with the lower tabs of the tool. Rotate the tool until the upper locator pin on the tool is aligned with the locator on the switch.
  2.  

Before sliding the switch onto the transmission it may be necessary to remove any burrs on the shaft by lightly filing the outer edge of the shaft.

  1. Align the switch hubs flats with the flats on the manual shaft, then slide the switch onto the shaft until the switch bracket contacts the mounting bosses on the transmission.
  2.  
  3. Install the switch retaining bolts and tighten them to 20 ft. lbs. (27 Nm), then remove the alignment tool and attach the switch electrical connection.
  4.  
  5. Connect the control lever to the manual shaft, install the nut and tighten to 20 ft. lbs. (27 Nm).
  6.  
  7. Lower the vehicle and connect the negative battery cable.
  8.  
  9. Check that vehicle starts in the Park and Neutral positions only. If the vehicle starts in any other position, loosen the switch bolts and rotate the switch slightly and tighten the bolts. Repeat this procedure until the vehicle will start in the desired positions only.
  10.  

Manual Transmission

See Figure 2



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Fig. Fig. 2: Common location of the back-up light switch

  1. Disconnect the negative battery cable.
  2.  
  3. Raise the vehicle and support it with jackstands,
  4.  
  5. Locate the switch on the left or right rear of the transmission housing (depending on the application), the back-up light switch is threaded into the transmission case. The speed sensor is held in with a separate bracket. Unplug the electrical connector from the back-up light switch.
  6.  
  7. Remove the back-up light switch from the transmission.
  8.  
  9. To install, reverse the removal procedures and lower the vehicle.
  10.  
  11. With the engine NOT running (for safety), place the gear shift lever in the reverse position and check the back-up lights work.
  12.  

 
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