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sprinkles08, Chrysler/Dodge/Jeep master tech
Category: Dodge
Satisfied Customers: 23131
Experience:  ASE Master and Advanced Certified, Chrysler/Dodge/Jeep Master Certified, Trans and Hybrid Specialist
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I have a 95 Cummins and after the vehicle warms up, the

Customer Question

I have a 95 Cummins and after the vehicle warms up, the tach, a/c and overdrive stop working. Tried replacing the pcm (twice) and the crank sensor
Submitted: 2 years ago.
Category: Dodge
Customer: replied 2 years ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Customer: replied 2 years ago.
Just curious when I might hear something?
Expert:  sprinkles08 replied 2 years ago.

Hello and welcome to JustAnswer!

Either the PCM is going down or it's losing crank sensor signal. If the PCM was going down completely then you should also be losing the fuel gauge and voltmeter. Loss of crank signal will cause the tach to drop out and lack of overdrive but it shouldn't prevent the a/c compressor from running.

Most likely the PCM is going down. You may have gotten replacements with issues, it could be losing a power or ground, an 8v or 5v reference circuit may be shorting to ground, or the sensor ground ciruit may be shorting to voltage.

Have the powers and grounds been tested at the time it's acting up?