Originally Posted by ucwellsy

Resurrecting an old post in hopes of getting some answers. Happen to have a similar project-
2004 Ranger 4.0 w/ M50DR1HD 4x4 swap into 2001 Ranger 4.0 auto 4x4. PCM and PATS system are from the 2004, Instrument Cluster and under dash wiring harness remain from the 2001. Treypauls write up got me pretty far but having the same issues you describe here; Temp sensor not registering AND "extra" plug from the 2004 Engine/transmission Harness(Rear most plug on harness, assume tail lights)

What I know so far;
Reverse lights are out, believe 2001 frame harness routes reverse light wires through the drivers side floor pan harness and to the column. If that is in fact what this rear most plug is for, should be able to figure out reverse light wire colors and splice extra plug into them. Thoughts

Temp Sensor vs Temp Sender - We have (2) Sensors in the thermostat housing. Both are "push-in" types with retainer clips. From what I understand, (1) Sensor goes to the gauge while the other sensor goes to the PCM to cycle the cooling system. We can test to see if the gauge itself is working by turning the ignition On, unplugging the sensor on the left and simply grounding out the connection to the block - should peg the temp gauge all the way hot. If so, we know the gauge itself is working and simply can't read the sensor.
Where I'm stuck; I've installed a new temp sensor for 2001-2003 Ford Ranger 4.0 and the gauge is still not reading it. Not even sure if the coolant is cycling through, but curious how you made out on this or if anyone else has suggestions.

Thanks in advance