2004-2008 Envoy Trailblazer Locked Up Shifter - How to Over-ride and Bypass the BTSI Interlock

WARNING! MAKE SURE THE VEHICLE IS STABILIZED AS WORKING ON ANY SHIFT RELATED PART MAY PULL THE TRANSMISSION OUT OF THE PARK POSITION! USE PARKING BRAKES AND WHEEL CHOCKS ON LEVEL GROUND! Most of all, be very careful, get professional help if you need it - Thanks for Watching!
Shifter Locked in Park? Here's a Way to Over-Ride the BTSI Shifter Interlock in an Emergency!
SAFETY WARNING! BE VERY CAREFUL WHEN WORKING ON ANY GEAR SHIFTER ISSUES! MAKE SURE THE VEHICLE CANNOT ROLL BY LOCKING THE PARKING BRAKE AND USING CHOCKS ON THE WHEELS - AT A MINIMUM THE REAR WHEELS SHOULD BE PROPERLY CHOCKED BUT ALL 4 WHEELS CHOCKED IS BEST. WORKING ON A LEVEL PARKING SURFACE IS ALSO CRITICAL!
GM Envoy / Chevrolet Trailblazer 2002-2008.
Link to Video: Three Common Transmission Shifter Problems / Won't Start 2006 Trailblazer Envoy Ascender Rainier SUV    • Three Common Transmission Shifter Pro...  
The original video on the BTSI for Trailblazer, Envoy, Ascender, Rainier was filmed at an angle that did not show the Over-Ride very well at the front of the video. This video may show that procedure somewhat more clearly. Just trying to be helpful. Thanks for watching, and please consider subscribing. Have a GREAT Day!

SAFETY WARNING! BE VERY CAREFUL WHEN WORKING ON ANY GEAR SHIFTER ISSUES! MAKE SURE THE VEHICLE CANNOT ROLL BY LOCKING THE PARKING BRAKE AND USING CHOCKS ON THE WHEELS - AT A MINIMUM THE REAR WHEELS SHOULD BE PROPERLY CHOCKED BUT ALL 4 WHEELS CHOCKED IS BEST. WORKING ON A LEVEL PARKING SURFACE IS ALSO CRITICAL!
You may need the assistance of a mechanic trained and experienced with this type of vehicle as It sounds like you could have more than one issue. That said, a shifter mechanism out of sync with the actual transmission can cause a lot of problems due to the signals the vehicle's on board computer is recieving and sending. The key switch will only crank the engine over if the actual transmission itself is in the park or neutral position (a malfunctioning shifter or cable mechanism may cause a difference in the shifter position and the actual transmission position.) I would begin by inspecting the shifter related linkages and mechanisms (ALWAYS STABILIZE THE VEHICLE FIRST). You may have a bad shifter cable issue or - possibly the cheapest to fix and most likely- only the grommet at the end of the cable may be worn/bad/disconnected. You also could have a BTSI issue keeping the shifter locked up, but that is less likely. There are steps on other videos that explain those issues. A first-step easy, cheap fix for that may be to pull the shifter lever boot up and try a bit of WD40 at the points shown in the video. As a diagnostic measure you could drill a hole in the side of the console in the right position (shown on the BTSI video) to manually release the BTSI lock -BUT BE CAREFUL TO ENSURE THE VEHICLE CAN'T ROLL IF YOU MANUALLY OPERATE THE BTSI SOLENOID!
AGAIN: WARNING! MAKE SURE THE VEHICLE IS STABILIZED AS WORKING ON ANY SHIFT RELATED PART MAY PULL THE TRANSMISSION OUT OF THE PARK POSITION! USE PARKING BRAKES AND WHEEL CHOCKS ON LEVEL GROUND! Most of all, be very careful, get professional help if you need it - Thanks for Watching!