OEM 2003 Chevrolet Trailblazer Body Control Module

2003 Chevrolet Trailblazer Body Control Module Parts and Q&A

• Q: How to replace the Body Control Module (BCM) on 2003 Chevrolet Trailblazer?

  A: Start by closing the Ignition Switch before working with bcm connectors. Disconnect the 40-way body wiring extension then move to the 32-way tan connector and end with the 24-way gray electrical connector. Realign the 24-way gray connector first followed by the 32-way tan connector and finally attach the 40-way body wiring extension. The Body Control Module can find electrical issues even with the power off and protects battery power by maintaining light operation but does not locate electrical problems in parts it controls. Activate the power down now mode through the scan tool to find out any remaining power use on those circuits. Do not contact electrical contacts on the body wiring extension or try to open the bcm housing because both remain non-serviceable components that must be replaced as a whole unit. Start your work with the negative Battery Cable's removal. For chevrolet trailblazer ext and gmc envoy xl installations remove both second-row seats while chevrolet trailblazer, gmc envoy, and oldsmobile bravada owners should move the left second seat into cargo mode. You can take out the edgroom electrical box panel to find and release the bcm sliding retainer. Pull it toward you to 40mm until it hits its stop. We disconnect the three electrical connectors which include the 40-way body wiring extension, 32-way tan connector, and 24-way gray connector from the Body Control Module. Pull the bcm upwards out of the rear electrical center seat. Fit the bcm slots first to the rear electrical center then push it down to install. Plug in the 24-way gray electrical connector first followed by the 32-way tan electrical connector then the 40-way body wiring extension. Press the sliding latch to connect the bcm to the rear electrical center by moving it towards the center as the locking post locks into place. Reinstall the rear electrical cover and choose either passenger positioning for the left second seat (when needed) or put back the left second row seat for chevrolet trailblazer ext and gmc envoy xl models. Close the negative Battery Cable connection while programming any new bcm functions.