A couple months back our truck didn't want to start so I got a new battery at Costco. My wife normally uses the truck when she has gardening jobs and it has been sitting a couple of weeks. Today it wouldn't start. When I replaced the battery I checked drain and it was really low (I don't recall how many ma the reading was, but it was very low). I'll charge up the battery and measure drain current again tonight. Seems like the battery should stay good for longer than a couple of weeks. Where should I look first for intermittent drain issues? The truck in question is a 2001 F150 XL xtra cab w/4.6 V8.

 

Who makes the battery?

 

I don't know who makes Costco's Kirkland brand batteries, but I have used them in a number of vehicles and they have been reliable for me so far.

I assume leaving a door ajar shouldn't be a drain, but that was one of my theories for a little while (she has been known not to shut the doors all the way).

 

leaving the door ajar, interior lights on, or a phone charger in will drain the battery.

 

I purchased a new battery about a month ago an left my truck on while I was working on her an forgot to start her an the battery died. so I jumped her an let her run for awhile, is there any damage to my battery or did I shorten the life of it or anything by doing that?

 

They say sometimes its better to put a full charge on a dead battery. Should not be any damage.

 

For some strange reason, some trucks with the auto-lamp module have the batteries drain faster. I simply turned mine off, and it could be a month before I had to worry about weak or no starts. Even if you left the door ajar, there's a relay that turns off the interior and bed lights (15 to 30 min). Disconnect the battery, and you should measure over 13 volts. A weak or battery that needs a deep charge would measure below 12 volts. I had an AutoZone 24 month battery, and on the 24th month, it started reading lower than 13 V. A week later, and multiple attempts at deep cycle charging, it was down to 10. Obviously a cell was in the process of giving up the ghost.

 

I had a similar problem my door ajar light would stay on and it finally died on me in a short period of time too so I disconnected the door sensors and still died pulled the accessory fuse to shut the inside lights off but the bed light stayed on so I got sick of these f ing games so I just pulled the drivers side door sensor right out of the damn door sure enough it worked! Best part is the door ajar light lights inside will turn on with any door open but turn off with the door shut so whatever the hell is going on with that I don't have a clue but I don't care it is working like new!