This storm's been hell on my fleet, broken backhoes, skid steers, and now my favorite 2500 it seems. Sounded like it was cranking a bit slow. Engine off, voltage shows 9-10 volts. Running, 13-14 volts. Batteries are less than 6 months old, terminals are clean. Service manual is with a friend so I'm flying blind, would love some ideas so maybe I could get it fixed tomorrow. My thoughts are a ground or voltage regulator. I've never had to deal with the alt on my truck, what's involved? Any helpful insight welcome, THANKS, Seth

 

Voltage reg is in the PCM, computer. If your voltage running is 13-14 volts the battery's should be charging. Have you alt. out put checked at an electrical shop. If your problem is in the PCM don't let them change it, you can add an external reg to fit it.

https://www.dieseltruckresource.com/...prog=1&lang=en

Floyd

 

Blackimpala, thanks for the reply. It helped me make sure that the charging system was working correctly. Took the batteries and had them load tested, they checked out ok. I think they were measuring low as I was having a hard time starting the truck, it was cranking slow. I may have run them down a bit. Pulled and cleaned every cable and and measured them on an ohm meter, all good. Charged up the batteries, still have a slow crank. Picked up a rebuilt (yeah I know) starter, and hope to get it in asap, and report back.

 

A rebuilt isn't bad as long as you kept your far superior OEM starter to rebuild later.
Never give the OEM away for a core.