Thanks for the idea. I had already checked that and verified resistance between block and sensor. I am completely stumped with this problem. I have electrical schematics of the gage, coolant sensor, PCM, and all wires and have checked all of them. All are good. My truck seems to heat up fine so I don't think it's an open stat. I think I'm going to drain the antifreeze and change the stat. Any other suggestions as to something I am missing would be appreciated. Thanks.