Something is draining my batteries over night, The battiers are less then a year old, but yet if I let my truck sit a day without driving it, my truck will be dead.

I get my truck jump started it will warm up and after sitting turned off will start like the batteris are brand new. So unless I start the truck up and let it run for 20 minutes everyday it will die....

any suggestions will be very helpful!

 

Get a testlight and set it up like the diagram below. If you have a drain, the light will glow bright.

If the light does glow bright, then leave it hooked up and start pulling fuses till the light goes out. When you find the right fuse, then that will be the circuit with the drain. Also make sure to take any wires off the battery that may have been added for amplifiers or anything else and see if the light goes out.

Since you have a later model truck, one thing you have to watch for is the accessory timer. After you turn the key off you will have to wait a few minutes to make sure that is turned off(the timer that lets you work the windows and the radio for awhile). This is a drain, and will make the light glow bright till it goes off. Also if you are testing with the door open or you have the hood open with a hood light, the courtesy light circuit will also make the testlight glow, since it's also a drain.

If you cannot find the drain with the fuses under the hood or under the dash, then take the wires off the alternator and see if the light will go out. If it does, the alternator has a problem and needs replaced.

 

I like Dave's idea. I'll have to bookmark this for future use!

When you turn the truck off, open and then shut your driver's door and it will kill the accessory circuit. Then all you have to do is wait the 30 seconds or so until the cab lights go out then you should be good to go. For the hood, just pull the bulb out of the hood light.

As a good measure, I would make sure that your battery ground connections are corrosion-free and are in good shape (solid contact, not loose). Also, make sure that your battery terminals are corrosion-free (you can clean them with a mixture of baking soda and water). It doesn't take much to really reduce the conducting ability to (charging) or from (supplying) the battery. You can also disconnect both batteries the first night too to see if they are dead in the morning (if you don't want to have them load tested at an auto parts store).

It's hard to pinpoint electrical issues like this. Everything feeds off of each other (alternator, batteries, connections). Any weak area can mask itself as a different problem or degrade the other components. The one positive thing is that it's not intermittent so it will be easier to troubleshoot.

Just my .02.

Best of luck!