03 F-350 ect stay cold not going past 138f degrees

[FordFanaticTony]

Installed new thermostat and ect sensor the vehicle stays cold. No codes during self-test. next step is taking an actual reading with a temp gun. Anyone ever seen this?

[forddieseldoctor]

Is that actually ect and not cht? If I remember right the ect sensor on those only make the gauge work and the pcm never sees it. 

[FordFanaticTony]

I replaced the coolant sensor on the front cover that goes by the thermostat housing.

[FordFanaticTony]

Just looked at the schematic. Going to check out the mat and eot also since they share the signal return from the ect.

[forddieseldoctor]

Oops. I mixed up 6.0 and a gas motor. Disregard the cht question. 

 

What’s the eot read when the coolant temp says low?

[cbriggs]

After a cold soak do ECT, EOT and IAT 1 & 2 all match? If it is an NTC thermistor as temp goes down, resistance goes up, so resistance in the circuit will show as low temperature. ( I can't open wiring diagrams on my home pc to verify, just brainstorming...)

[FordFanaticTony]

Well glad I looked at the schematic beforehand. Someone worked on this 03 before so they plugged the IAT2 to the ECT and vice versa. Always beware of the previous guys work. Thanks fellas for any tips and advise as always.

[cbriggs]

Hahaha. That's a new one. Glad you figured it out.