I have purchased 05 OEM fans and a Nelson harness for my 2000 Z71 Tahoe with 5.7 liter eng. This is the old body style. Nelson failed to tell me that the harness they sent me would not work on old body style. But I can make it work. What I need to know is there a different pin in the blue PCM plug that can give me a ground based on eng. temp???? My blue PCM plug only has 32 pins. Called Nelson and they were not much help. They said to install a switch for low speed fan or I could send back the harness for a 5% restock fee. Any help is greatly appreciated.