Dorman 599-004 HVAC Control Module - Front or Rear

HVAC Control Module for Trailblazer, Envoy, and More

Restore cabin climate control operation with this Dorman HVAC Control Module, part number 599-004. It is a direct replacement for the original manual HVAC control unit and is fully tested before release, making it a practical solution for vehicles with failed temperature, blower, or mode control functions.

• Direct replacement HVAC control module for manual climate systems
• Fits front or rear positions, depending on vehicle application
• No programming required
• Pin-style terminals with 16-pin configuration
• Black bolt-on housing with female connector and male terminals
• Compatible with rear window defogger-equipped applications

Detailed Product Overview

Dorman 599-004 is an HVAC control module built for manual climate control systems in select GM-platform SUVs and related models. It replaces the malfunctioning original unit to restore normal HVAC operation without requiring programming. This part number 599-004 is designed for vehicles such as the Chevrolet Trailblazer, GMC Envoy, and Buick Rainier, along with the Saab 9-7x, Isuzu Ascender, Trailblazer EXT, Envoy XL, Envoy XUV, and Oldsmobile Bravada.

This module uses a 16-pin, pin-terminal layout with a female connector and male terminals, and it mounts with a bolt-on design. The unit is intended for manual HVAC systems with rear window defogger functionality. This part cross-references OE-style numbers 10395426 and 15022101 for the same application.

Common Problems This Part Can Address

• HVAC controls that stop responding
• Loss of blower speed, mode, or temperature adjustment
• Intermittent or inoperative climate control panel functions
• Failed manual HVAC control operation in front or rear locations
• Defogger-related control issues on supported applications

Installation Notes and Fitment

Compatible With 2003-2009 Chevrolet Trailblazer, front or rear; 2003-2009 GMC Envoy, front or rear; 2005-2009 Saab 9-7x, front or rear; 2003-2008 Isuzu Ascender, front or rear; 2004-2007 Buick Rainier, front or rear; 2003-2006 Chevrolet Trailblazer EXT, front or rear; 2003-2006 GMC Envoy XL, front or rear; 2004-2005 GMC Envoy XUV, front or rear; and 2003-2004 Oldsmobile Bravada, front or rear.

Installation is bolt-on and does not require programming. Verify connector style, pin count, and manual HVAC configuration before installation. This module is intended for vehicles equipped with a rear window defogger and should be matched to the original control layout for proper operation.

Quality Assurance

Dorman replacement electronics are fully tested before release to help confirm proper function and fit. The part is built as a direct replacement for the original HVAC control module used in the listed applications.