Download The plenum lower is formed from laminated steel. This steel is constructed by bonding 2 pieces of cold rolled steel (1) with a viscoelastic layer of adhesive (2). MIG welding laminated steel does not meet GM Corporate standards for structural integrity. As an alternative, all factory welds may be replaced by using the rivet and adhesive bond method described in the installation portion of this procedure. The rivet and adhesive bond method must only be used in the areas described in this procedure. Removal Procedure Caution: Refer to Approved Equipment for Collision Repair Caution in Cautions and Notices. 1. Disable the SIR system. Refer to SIR Disabling and Enabling . 2. Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection . 3. Remove all related panels and components to gain access to the upper plenum panel. 4. Remove the sealers and anti-corrosion materials from the repair area, as necessary. Refer to Anti-Corrosion Treatment and Repair 6. Reposition the body side and the windshield flange to aid with the removal of the upper plenum.