UPDATE: Today I got the "new" PCM and installed it. Checked Voltage at the battery after starting and it was 14.6. Gauge working. NO CHECK ENGINE LIGHT Went for a test drive and the gauge dropped off about 5 minutes into drive. Came home and checked voltage, back at 12.3. What the heck!! could there be a short somewhere between alternator and PCM? why would it be good for a few minutes then go out?

 

Do you have a scanner that can read the battery temp sensor??? Pretty sure if the PCM thinks the battery is too hot, it will stop charging it.

 

thanks for the information, I will be taking the truck to a dealership for a thorough scan. Last shop didn't have the proper equipment.

 

Dealership was able to secure (zip tie) the wiring harnes that was having an issue. After looking at another problem on the truck I found an area that was damaged by an animal (field mouse or rat?) on the back side of engine / passenger side.

I will look for a replacement (used since they stoped making the wiring harness in 2012) and go from there.

Thanks for all the comments/sugestions! Carl B