Dorman 599-100 Transfer Case Control Module

Transfer Case Control Module for Electronic Shift Systems

Restore transfer case control on select GM and Isuzu trucks and SUVs with this Dorman replacement transfer case control module. Built to match the original module’s function and performance on specific vehicles, it is a cost-effective solution for electronic shift transfer case issues.

Part number 599-100 is a direct-fit style replacement for vehicles equipped with RPO code NP1, including Chevrolet Blazer, GMC Jimmy, Chevrolet S10, GMC Sonoma, and Isuzu Hombre applications.

Key Features

• Replacement transfer case control module for electronic shift 2-speed transfer cases
• Blue connector color with pin terminal type
• Includes transfer case control module only
• Engineered to provide the same function and performance as the original module on listed applications
• Fits select 1998-2005 Chevrolet Blazer and GMC Jimmy models with RPO code NP1
• Fits select 1998-2004 Chevrolet S10 and GMC Sonoma models with RPO code NP1
• Fits select 1998-2000 Isuzu Hombre models with RPO code NP1

Detailed Description

Dorman 599-100 is a transfer case control module replacement for vehicles with a 2-speed, electronic shift transfer case and RPO code NP1. It is intended for drivers dealing with transfer case communication or shift-control problems on Chevrolet Blazer, GMC Jimmy, Chevrolet S10, GMC Sonoma, and Isuzu Hombre models. This module is built to restore the original control function without requiring a full transfer case replacement.

This part cross-references Cardone Reman 73-42100 for the same application.

Common Issues This Module Can Address

• Transfer case not shifting between 2WD and 4WD modes
• Intermittent or inoperative electronic shift control
• Loss of transfer case module communication
• Faults related to the original control module on NP1-equipped vehicles

Installation Notes and Tips

Verify the vehicle’s RPO code NP1 before ordering. Confirm connector color and terminal style match the original unit, and inspect related wiring, grounds, and transfer case components during diagnosis. This module is intended for the listed applications only, including 1998-2005 Chevrolet Blazer and GMC Jimmy, 1998-2004 Chevrolet S10 and GMC Sonoma, and 1998-2000 Isuzu Hombre.

Quality Assurance

Dorman replacement parts are developed to match original equipment function on specific applications. Part number 599-100 is built as a direct replacement module for the listed vehicles and transfer case system configuration.