Sooo everyone, I bought this truck a month ago, noticing temp gauge didn’t work, was thinking replace the ect sensor and bam it’ll work, but that’s not the case. I replaced the ect sensor and also verified it works! Using my ohm meter and diff water temps measuring resistance, also replaced the cht sensor. I jumpered the two pins on the ect sensor and it pegged hot, (ruling out a bad cluster) I’m running out of ideas, also replaced pigtail on the ect sensor. I only have two codes ( which don’t trigger cel) p0171 and p0325. Ive replaced thermostat, and felt it open for hot water in upper rad hose. The guy got the motor rebuilt before me with paperwork. Any ideas or tips would help.ive hooked a live data scanner to it and it read the temp @ 140 on cold startso I guess pcm works? And wiring? Hell idk... Thanks!! Also has tranny cooler lines cut at radiator and has a aftermarket tranny cooler (not sure if that matters lol) 1998 Ford F-150 5.4 v8 4x4 lariat super-cab. Also has a nice fab tech lift, not sure if a wire got messed up some how?

 

The Temps were showing 140 at startup? It should be around ambient at startup.

 

I’ll have to check again man maybe I had started it for a bit and let it cool off a little maybe