I have a 99 F150 4.2 liter. temp gage show redline but engine is not over heated. let it run in my garage for 20 min in the red and then I shut her off and turned her back on; gauge went to normal position. fuses look good. I cant seem to locate my temp sending unit though. there is a plug to the right of my thermostat housing but can locate where the unit is!!!!