Son's 2000 F-150 5.4L engine has a P0125 code and the temp sensor is not working. Have looked all around the thermostat housing along the coolant bar but no temp switches are located on it (behind alternator nor to the left or right of the alternator). There is a plug in the center of the coolant crossover/thermostat housing behind the alternator -- looks to be where the pictures show the ECT switch is supposed to be located. Anybody know where to look on the 2000 5.4L Triton engine for the temp gauge and ECT switches...they ain't on the front of the intake near the thermostat housing!

Thanks,

Larry

 

There is a cylinder head temperature sensor. It is located on the passenger side head.

 

Thanks for the reply. Do we have to come up from the bottom of the engine to get to it? I have looked all over the top of the engine -- I can see the fuel injectors and plug coils but absolutely no screw-in type sensor or wires for a sensor.

The picture I have shows a 4.6L engine and says "the 5.4L switch locations are similar" - no, they are not...LoL!

 

IIRC it is on the top of the passenger side head towards the middle.

 

There is only one on these trucks. Its on the driver side head underneath the intake. Its a real bear to get to without removing the intake. Im not sure if it can be done.

I had a problem with mine awhile back. The temp gauge was jumping around and the truck was pinging bad. Ended up being the connector that was 6 inches away from the temp sensor. It was corroded.

 

Whoops, I guess I was mistaken.

 

Thanks - About where in relation to the injectors/coils can I see this switch? I've been using a high powered flashlight and still can't find it! I thought I was going stupid not being able to find it...LoL! I've been looking all over the engine, hoses and radiator...they did a good job hiding it! It's beginning to sound like a job for a technician...

 

According to the manual for my '08 the cylinder head temperature sensor is located at the upper right rear of the engine.

 

Usually, a P0125 is cause by a thermostat that is worn out...

 

It runs out the front of the motor from under the intake manifold. it will go on the right side of the alternator around the front side of the drivers side head. It will then go up into the loom that injectors are plugged into.

somewhere in there is a connector for the sensor.

Basically front of motor though, coming from underneath the plastic intake. You cant see the sensor itself.

 

we're changing that out today...I'm hoping that the temp gauge not responding is due to the thermostat too...hopefully we won't have to change the ECT sensor too!

 

Thanks everyone for the replies. We've got our fingers crossed the thermostat change takes care of it!

 

BURNSTOUGHFORD

You got it right! The ECT switch is under the intake, front just under the intake runner on the driver's side (this is a 2000 F-150 with "L" code 5.4L).

Replaced the thermostat and the gauge now goes to the middle and stays there. Should take care of the P0125 DTC -- haven't driven it long enough to check -- but considering the temp gauge was at the bottom (cold) while driving before changing the thermostat it should fix.

Thanks everyone.

 

thanks for all the responses to my earlier post. after much though examining, with the air intake removed, i found the little sucker. mine is on the driver's side head, underneath the intake manifold,with a pigtail connection to the wire harness behind the thermostat housing. how one would change this is beyond me. i can't even touch the thing with my hand. i would guess you have to remove the intake manifold. i tested the sensor ,at the plug and it shows it's ok. my guess seems to point to the thermostat,or possibly a bad radiator/tank cap. we'll see..!!!: burnstoughford i think you'r right....