The water temperature gauge is pegged out all the time on my 1991 Chevy Suburban. The gauge reads far past the max scale reading even when the truck has been off for multiple days. I disconnected the single-wire connector from the sender on the drivers side head and even that doesn't cause the gauge to change. I'm going to pick up a 220 and 150 ohm resistor to build tool J-24538-A listed in the factory service manual (http://coloradok5.com/forums/showthread.php?t=263131). Hopefully I don't have to pull the gauge cluster and repair it or get it repaired since it's a pain to pull. Any ideas what's going on and how to troubleshoot it and fix it?