Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2008 Hummer H3 L5-3.7LFACTORY OEM SERVICE PROCEDURE
Transmission Position Sensor/Switch: Adjustments
Park/Neutral Position and Backup Lamp Switch Adjustment
Important:
* The following procedure is for vehicles that have not had the switch removed or replaced. If the switch has been removed or replaced, refer to Park/Neutral Position and Backup Lamp Switch Replacement (3.7L) (Service and Repair)Park/Neutral Position and Backup Lamp Switch Replacement (5.3L) (Service and Repair) for the proper adjustment procedure.
* Apply the parking brake.
* The engine must start in the P (PARK) or N (NEUTRAL) positions only.
* Check the switch for proper operation. If adjustment is required, proceed as follows:
1. Place the transmission range selector in the N (NEUTRAL) position.
2. With an assistant in the drivers seat, raise and support the vehicle. Refer to Lifting and Jacking the Vehicle (Service and Repair) .
3. Loosen the park/neutral position switch mounting bolts.
4. With the vehicle in the N (NEUTRAL) position, rotate the switch while the assistant attempts to start the engine.
5. Following a successful start, turn the engine OFF.
Notice: Refer to Fastener Notice (Fastener Notice) .
6. Tighten the bolts securing the park/neutral back up switch to the transmission.
Tighten the park/neutral back up switch bolts to 27 N.m (20 lb ft).
7. Lower the vehicle.
8. Check the switch for proper operation. The engine must start in the P (PARK) or N (NEUTRAL) positions only.
9. Replace the park/neutral position switch if proper operation can not be achieved. Refer to Park/Neutral Position and Backup Lamp Switch Replacement (3.7L) (Service and Repair)Park/Neutral Position and Backup Lamp Switch Replacement (5.3L) (Service and Repair) .
Factory Service Tools
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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