Hello all! I'm new to owning a diesel truck and am having a few issues.

Truck is a 2006 3500 megacab. Check engine light comes off and on and when it is on and I do the key turn for codes it is giving me codes for my Fuel Rail Sensor, My security system, and 2 other things I can't think of right now. I've also noticed my engine is slow turning over, my lights interior lights tend to dim and brighten until the truck has been running for a bit, and the blowers seem to lose power as well until the truck has been running for a bit. After the truck has been running and I go to restart within an hour she fires right up and doesn't have any of the dimming etc. This is leading me to belive my Batteries are involved.

Seeing as how I'm new to this truck I am wondering if I am on the right track and also if I do need to replace my batteries do I always do both at the same time or have them checked to see if one is bad and the other is not. Also what is a reccomended battery and what should I expect to pay for them and how long should I expect them to last?

I want to thank you all in advance for helping me out and appologize for my inexperience. I would rather ask here and get an understanding before some Mech trys to take my money; especialy as I normaly do all engine work myself as we are military and have access to a full shop with pretty much every tool I need. So, once I'm armed with proper information I can very likely do it myself.

Tnx!

 

the bright and dimming is normal until your intake air heater warms up, watch your volt meter when you first start your truck it will go from around8 to around 15 or so srveral times till the heater for the air intake has warmed up enough

 

Your truck has a grid heater and when its a certain outside temp I think its 40 degrees F or below. That will turn on and cycle for a few minutes after start up... What is really weird that Alt. don't charge right away either... Some say there is a battery temp sensor under one of the batteries. the battery has to get to a certain temp before the Alt will charge...

But now its time to check your batteries. Disconnect them from each other and test them using a load tester. Once that is done check all grounds on vehicle.. On the drivers side inner fender their is one and where the battery cables hook to is another. If any one else can Chime in on this if there is anymore at a location that I didn't know about...

 

I agree with them, check the batteries first, see if they're good or not. If you end up replacing them, see if the problem goes away, and if it doesn't, might need to check the alternator also...