Details: You can use this harness to directly connect your electric fan upgrade through the ECU and let it control the fans (ECU does not need to be reflashed). The harness is preset to control your dual fan and comes with GM connectors for 05+ trucks. With this harness you don’t have to worry about the fans kicking in or using those dreaded probe thermostats that never work properly. This is a must when upgrading your truck to electric fans. Fits: For 1999 2000 2001 2002 2003 2004 2005 2006 ECU Control Part Number: 7L5533A226T Package Includes: 1* Electric Fan Wiring Harness Professional installation is highly recommended.