Hey guys, so my truck will go into o/d when the temps are cool. I’m refraining from saying “cold” because it doesn’t ever get cold where I am. Relative to most of the world. Haha

 

once my trans temp gets up around 100 deg F my pcm doesn’t send the ground signal to engage o/d. It will hold as long as I’m in it, but once disengaged it will not re engage as long as trans temps are above 100 deg. 
 

I checked the resistance that the temp sensor is sending to the pcm and it is accurate, as long as the key is off or the pcm is unplugged. As soon as I plug it in or turn the key on I lose about 400ohms resistance. Idk why. Plz help. 
 

I got a reman pcm from Chrysler and it’s not very old. I’ve tried running a resistor in-line the sendor wire but idk if I didn it right because it didn’t yield good results. 
 

 

plz help. This truck has been a tough fighter. Haha

Maybe @Dynamic can help 

You can't check resistance on an active circuit. You'll get all kinds of useless readings. You're going to want to check voltage with the circuit active. Check for voltage on the signal side of the sensor. It will change with temperature.

 

You shouldn't have any resistors in the circuit. You can check for voltage on the ground side (PCM side) of the OD solenoid. It should read battery voltage until the PCM commands the solenoid on. At that point, it will drop to zero (or near zero) voltage.