i have a 94 f150 with an i6 and 5 speed. the temp gauge just started acting funny. now when the truck is cold in the morning, the gauge reads like it's all warmed up and normal. then when the truck warms up the gauge is pegged on the hot side. after a while, like 10-15 minutes of this, then the gauge just plops down to normal and reads normal till you shut off the truck. then after the truck cools off, it starts all over again. is there a way to check the gauge/ sending unit? where is the sensor located? all help would be greatly appreciated. after this started i've done a good flush on the system and all fresh coolant
thanks, mark

 

The stock "gauges" on these trucks suck. Then sending unit is probably going bad.

Aftermarket gauges are a great investment.

As for the location of the sender I got this from google.(not an I6 guy)

"rear of the head right below the exhaust manifold..straight up from the starter"

 

sounds about right to me you hit it right on the head

 

thanks for tha answers. i found the switch, wow what a godforsaken place to put that! anyhow, i grounded the gauge and then it seemed to reset itself so the needle pointed to the cold side and it seems to be working normally now, go figure. again, thanks mark