2007 Expedition XLT.... so confused I could burn my truck

Quick back story....sitting at sons football practice with a/c on, suddenly there was a click and the air stopped working, it blew hot air. Engine light came on, temp gauge dropped to zero slowly.

Code read coolant temp sensor, which no one in my State can show me where it is. After three dealerships telling me it should have one, Ford finally said it only has a cylinder head sensor. Replaced it, twice, still no temp reading on gauge and engine light on. Still reads same code. When we start the truck for the first time each day, it starts smooth. Once warmed up, and then started, it acts like it's dumping fuel, like it's reading it's cold. Was told it was the computer, replaced it, but still problem. I'm at my wits end with this truck, hopefully someone can help me.

Welcome to the site.

I would check out FORscan or a similar product plus an OBD2 adapter so that you can see what data the ecm is receiving from the cylinder head temp sensor as you troubleshoot. You'll probably end up tracing/inspecting the wiring harness.

What Stamp's telling you is that the better code readers can read the data from each individual sensor and display the voltage -- or in this case the temperature -- on screen. This way you can tell that the problem is indeed in that temperature sensor. Then you can use the reader to diagnose the sensor, the plug and the wiring that goes to the sensor in real time. Trying to troubleshoot stuff like this without that kind of reader is very difficult.

With the real-time reader, you can just wiggle the sensor wiring and usually tell if there's an intermittent wiring problem or corroded plug. Most code readers could also help identify any other temperature sensors in the truck, which may be one you're missing.

I use Auto Enginuity with a Ford enhancement on a laptop, but it costs about $300. FORscan is virtually free but it seems there's a longer learning curve. Once you have this reader all sorts of troubleshooting will be made much easier.

None of this stuff's too simple and the software requires some time for learning, but the money you save from not "throwing parts at problems" makes it a great investment.

Ok, so I changed the connector to the cylinder head temp sensor, but I'm still getting an engine light and temp light, and the temp gauge is still not working. I'm going to try Forscan first, any other ideas? Could it be in the dash cluster?

As I recall Ford uses some ribbon cable connecting parts of the dash cluster. Some are fragile. I had a loose one on a former Explorer.

-- Chuck

Why change a connector that hasn't been proven faulty? Now you have added another possible failure point in the future?

Did you solder and heat shrink the connections?

Stop changing parts and diagnose the problem. We told you how. You may be adding new problems, my friend.

A teacher I knew in the vocational part of public schools told a story about a state competition between the "best" tech students one year. The goal was to determine why their lawn mower engines wouldn't start.
Most of the students tore the engine and carbs down to the individual components and couldn't figure out why they wouldn't start.
Sad that none of them checked for gas in the tank.....

Mike, I don't know why they keep telling you your 07 doesn't use a coolant temp sensor. Auto zone and Rock auto list them. Auto zone gives Su8756 and Su8781 as part numbers. Maybe one of our members can elaborate as to location on motor. I'm surprised your Dealer is such a bonehead, but what else is new!

Sent from my N9131 using Tapatalk

If you Google "Su8756" it comes back as both a coolant temp sensor from a few sellers and cylinder head temp sensor from others.