Where is the temp sensor on a 2003 ranger 4.0? I have a sensor right next to the last spark plug on the driver side, but there is no wire going to it and it doesn't have a plug on it as the pictures show. I have look all over for a loose wire but can't find one, and my gauge doesn't work.

 

On 2003 4.0l SOHC it should be on the thermostat housing under the throttle body

There should be 2 units at that location
ECT sensor, 5volt, only used by the engine computer(PCM)
ECT Sender, 12volt, only used by dash board temp gauge

The sender should have a Red/White stripe wire
The sensor a Light green/red stripe wire

Picture here: https://howtoreplacefordthermostatho...t-revealed.jpg

Thats the two units, they don't screw in, there are slide in clips that hold them inplace

 

The TempSensor@TStatHousing with the GrayHarnessSocket connects to the InstrumentCluster TempGage.
The TempSensor@TStatHousing with the OrngHarnessSocket connects to the EnginesControlMod.

@eagle0551
Regarding the sensor on side of the engine:
Are you possibly talking about the OilPressureSensor\Switch on the foreward leftside below the PowerSteeringPump
& OilPressure "pseudo" Gage (looks like a gage, but is only an Off\On indicator) in your cluster?

 

Thank you this helps a lot.
Jerry