The dumb corroded junction connector on the inside of the LH fender. Between the fuse box and the air cleaner. Follow the red wire from the driver side battery that goes straight back towards the cab. Not the big cable that goes across to the other battery. It goes into a little plastic box. Open that up and I'll bet you find the problem.

There's a thread on here with pics. NoRalph came up with it. It should be a sticky.

 

Cleaned it up. Still shuts off after idling a while. Had new fuel pump put on it couple weeks back think that could have anything to do w/ it. Thanks for the help.

 

Thanks so much Dave P. Your knowledge was dead on. Cleaned connector by air intake. Then reprogrammed. Because of past battery problem. All is good! Thanks again.

 

2002 F-250 7.3 HD Banks Six Gun. Had battery problem. Motor cranks then shuts off. Clicking behind fuse box under dash. Clicking from relay under hood driver side. Will turn over but no crank. New battery. New relays. Samething. Maybe ground? Pulling the rest of my hair out. New fuel pump about 3 weeks ago. My help greatly appreciated!

 

You put up an exact copy of the original post last night. Did the problem come back, or is this an accidental repost?

If the problem is back, go to that connection again. "Cleaning" isn't generally enough. The corrosion gets into the wires and turns the conductors to green dust. Having to cut back, or even replacing the wires is usually required to perform an effective fix.

You can check it with your meter. Make it "do it". Leave the key on. Open the hood and uncover the fuse box. Put your meter on 20 VDC scale. Put one lead on the (+) side of the Driver side battery. Put the other meter lead on any Maxi Fuse "test hole" (the little holes in the tops of the fuse). Any voltage reading greater than a few tenths indicates substantial resistance between the two points. If you see close to battery voltage in this test, the 'dumb little box' is between these two points. You need to work on it again.

 

Yep it happened again. Had bad battery, no good under load. Now worried about the other one. Have it checked sat. Thanks for your info on corrosion. Didn't even think about wires. Will get new ones. Someone told me about a ground, driver side behind cover on finder well. Goes from motor to fire wall. Going to tear into it sat. Hopefully I will get my baby running. Miss that old truck. Thanks so much for you help. I've already learned a lot on this site. I still have a lot to learn. Thanks again for your help!