Case of the mysterious power drain...Please help!

[BigWhiteThreeFifty]

Well, so about two weeks ago, I left the truck outside for a few days and it froze, not even a AAA truck could jump start it; the dealership got it jumped and running, but when I went in and paid for the repairs then went back outside to start the truck, it did nothing but click. They got the battery truck out there, and it started right up. I got my block heater installed and had no problems until about a week ago when I parked in a self car wash and went to go get change, came back about 15 seconds later and the battery was completely dead just out of the blue. So I went and bought completely new batteries, thinking it was a dead cell in one or two of the batteries. That seemed to work perfectly, and the truck is plugged into the block heater every night. Well, I just went out to start it this morning, and the week old batteries (Duralast golds), are completely toast! No interior lights were left on, nothing plugged into the power socket, just the block heater plugged in overnight, and when I went to warm up the glowplugs, the radio said low battery, and the truck proceeded to commit suicide. Now it won't even click when I turn the key. Any help? Surely these batteries couldn't have gone dead in a week...could there be some battery drain I don't know about maybe?

[colberjs]

Maybe a bad alternator

[Jarrod B]

have you change the starter relay?

[symbols]

Sounds like a glow plug relay. I just helped another member with that issue. It would only do it some of the time and when I would test it wouldn't do it. The glow plugs pull over 100 amps I think. I don't know what year model you have though. You need to fill out your sig so we know what we are looking at

[BigWhiteThreeFifty]

It's am '05 6.0....the dealership checked all those things when it first died and didn't find anything worth replacing, but I'm going to get new batteries under the manufacturer's warranty and then take it over to Ford anyways; if it's the gpr, it should be covered under my warranty.

[symbols]

Well, like I said his was only doing it when I wasn't looking....