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HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4.2 S, 4WDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 1449 (SHIFT INTERLOCK SYSTEM)DESCRIPTION AND OPERATIONAUTOMATIC TRANSMISSION SHIFT LOCK CONTROL DESCRIPTION AND OPERATIONAUTOMATIC TRANSMISSION SHIFT LOCK CONTROL SYSTEM
2003 Chevrolet TrailBlazer 4.2 S, 4WD

Automatic Transmission Shift Lock Control System

2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Automatic Transmission Shift Lock Control System
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2004 Oldsmobile Bravada, 2004 GMC Envoy XUV, 2004 GMC Envoy XL, 2004 GMC Envoy, and 2004 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.

The automatic transmission shift lock control system is a safety device that prevents an inadvertent shift out of PARK when the engine is running. The driver must press the brake pedal before moving the shift lever out of the PARK position. The system consists of the following components:

  • The automatic transmission shift lock control solenoid
  • The automatic transmission shift lock control switch

With the ignition in the ON position, voltage is supplied to automatic transmission shift lock control switch. Voltage flows through the normally closed contacts of the automatic transmission shift lock control switch to the automatic transmission shift lock control solenoid. The automatic transmission shift lock control solenoid is permanently grounded. This energizes the automatic transmission shift lock control solenoid causing the transmission shift lever to be physically locked in the PARK position. When the brake pedal is pressed the contacts in the automatic transmission shift lock control switch open, de-energizing the automatic transmission shift lock control solenoid. This allows the shift lever to be move out of the PARK position.

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