I have a 2010 Ram 2500 Megacab, 6.7 cummins, automatic. Problems started a week ago. Got in one cold morning, I was on the Mountain, and only a click trying to start. I assumed it was bad battery, or poor connection. After cleaning battery post and looking at connection. Still the same one click. On the one click I would loose all power to everything. After turning key back to off all would come back. Resets clock and sometimes also get message to check trailer brake system. Batteries were each testing high 12 volts. With the help of others. Also put volt meter at starter. I have no drop in voltage there. I jumped the solenoid at starter. It started right up. Had no more problems for a week.
Now the problem is constant. In order to start I have to jump at the starter.
I have swapped starter relays.
Remote start will not work.
I have tried starting in Neutral, same thing.
I'm aprox 100 miles from a Dealer, and would rather do it myself anyway.
I'm thinking possibly ignition switch or TPIM. I have pulled the TPIM and see no visual problems.
Any help is appreciated.

 

Do you have a check engine light?

 

No check engine. I tried looking for DTC by turning key on and off three times quickly and nothing gets displayed either.

 

Unfortunately, you need a code reader to pull any codes.

Honestly, it sounds like it could be the batteries. You may be reading 12V, but one battery could be going bad. You jumping at the starter is merely bypassing the electronics.

I recommend having your batteries load tested. While it is possible it could be the TIPM, I don't think it is likely as it would set the check engine light and there would be codes associated with it.

The click when trying to start is a typical sign it is the batteries. The same thing happened to me around 2 years ago. Truck had been working fine, then one morning went out to start it and click. Instead of fiddling around with it, I just replaced the batteries with the heavy duty ones from Sears. No problems with the batteries since then.

Now, I have been having TIPM problems since 2011 (you can find my threads on those issues), that would cause the truck to not start. It would have a loss of communication among other issues preventing it from starting. Once everything woke up, the truck starts and runs just fine. Doesn't sound like your issue.

 

Batteries were tested removed from truck. I agree with you that it may be batteries. That was my first thought. My reason for now not thinking it is I have cranked for a total of up to maybe 15 minutes with no success of starting and it still cranks strong.
I will be taking to a shop tonight to have codes read if it will start and I can get it there.

 

Tonight, It started and ran for about 3 seconds and shut off. Can't get it to start now only turns over jump starting. And now check engine light is on.

 

Hmmm. That's strange.

Definitely something going on. Could it be that it isn't getting fuel?

How many miles on the truck? When was the last time the fuel filter was replaced?

Have you done any modifications recently?

 

Well well, It did turn out to be both batteries. My volt meter is bad as well.

 

Glad to hear you got it fixed