Engine/Transmission (1994 - 1998) transmission temp sensor test procedurev 47RH??

[dieselworld]

What is the transmission temp sensor test procedurev 47RH??

I am working on a 1994 Ram 3500 Cummins. I have the dreaded no overdrive at times scenario. Fluid levels are correct. Removed the TPS, cleaned and reinstalled. Cleaned all battery terminals, cables and ground connections. I am a little foggy on testing the trans temp sensor. Mine has 2 wires black and purple. I have 5 volts on the purple wire, I assume the black is a ground.



I checked the OHM's on the temp sensor while hot and it reads open, but would this not make the "trans temp" light come one? With the harness pluged in to the sensor the light is NOT lit.



What is the proper test to bypass the trans temp sensor to see if it allows overdrive?

 

[ABorchard]

Can't say it's the proper way but what works excellent is to unplug the sensor connector and jump across the two wires with a 1000 ohm resistor. Leave the sender disconnected. The design of the sensor plug makes it easy to jump across the leads with no changes at all to the connector.

The 1000 ohm resistor will trick the pcm into thinking the fluid temp is 90°, and will stop the transmission from hunting if the sensor is indeed the problem.

 

[dieselworld]

Ok I will go by Radio Shack and pick up the resistor.



Will the "transmission temp" light on the dash stay off even with the sensor disconnected and resistor in the plug?

 

[Joe G.]

I have a 700 ohm resister in mine. Works that same as Art's 1K resister. The PCM has no idea that the sensor has been replaced by a resister so no trans temp light. It would be a good idea to get a trans temp gauge because with a resister in there the temp light will never come on regardless of how hot the trans gets.