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brownjeff, ASE Certified Technician
Category: Dodge
Satisfied Customers: 13886
Experience:  17 years experience, ASE certified, dealership certified, Service Manager for 15 years,
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95 Dodge Ram 3500: no tach, battery fine..pcm

Customer Question

I have a 95 Dodge Ram 3500 Dually with a charging problem simlar to others I have been reading about, has a new alternator checked the 140 fuse, no tach, battery voltage only at all points. When I was checking for voltage at the back of the alternator (after checking all connection points etc) when I touched the higher stud of the field with the meter I presume; it triggered the regulator and everything started to work fine after shutting the truck off and restarting everything was normal, next morning started it again and we are back to the original problem. Is this the ASD relay or a bad PCM or?
Submitted: 7 years ago.
Category: Dodge
Expert:  brownjeff replied 7 years ago.
Gas or diesel engine?
Customer: replied 7 years ago.
Sorry about that, 5.9 Cummins with automatic thanks!
Expert:  brownjeff replied 7 years ago.
The reason I needed to know is on a gas engine there is a battery temperature sensor and on the diesel there is not. If the alternator is good and having a power problem getting voltage to it then the problem is in the pcm. If it were the asd it would effect more than just the charging system.
brownjeff and 2 other Dodge Specialists are ready to help you
Customer: replied 7 years ago.

Well like I said it did affect the A/C clutch and the alternator; if you are convinced it is the PCM can I use a used one without any programing so I can verify if it resolves the problem and also is there anything else I can check I am familiar with electrical systems,meter operation, current guage etc.. just need a starting point or common problem area with these trucks thanks, Konrad

Expert:  brownjeff replied 7 years ago.

You can check pin 57 of the ecm to make sure getting power from the asd relay.


I will attach a wiring diagram to help.....












Customer: replied 7 years ago.
What is the most common problem in these trucks? And thanks for the schematics I will try to work on it over this weekend. Also what about my earlier question about trying a used PCM, Thanks!
Expert:  brownjeff replied 7 years ago.
Yes you can use a used pcm......and other than the alternator the pcm is the next most likely cause.
Customer: replied 7 years ago.
Thanks for the info!
Expert:  brownjeff replied 7 years ago.

No worries.....


Good Luck,



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