Hi:

I have a 1997 F-150, extended cab with 5.4L engine. I don't drive it very often, maybe once every two weeks. Something is draining the battery, for the truck won't start if not started for a couple of weeks. If I start every 3-4 days, no problem. I didn't have this problem before a remote start was installed.

Any ideas on how to determine is draining the battery?

Thanks

 

Maybe the remote start or if you have an alarm, plus the cold weather.

 

disconnect the negative battery cable. connect a DVOM on the 10amp scale between the negative battery post and cable. This will measure the draw on the battery. Make sure all the doors are closed and wait about an hour after connecting for all the modules to shut down, then look at the reading. Best to be below .050amps

 

If the battery is old, the alarm system may have added enough extra drain to bring about the problem.
This system as well as the PCM has a 'keep alive' drain and to enable the alarm to respond to an intrusion.
I would test the battery for capacity, the alternator for leaky diode stack and measure the alarm drain as well to find all possible causes.
You may now have more than one issue.
Even new/used vehichles on a lot have to be started every month or so to keep their batteries from going flat.

 

May sound trivial but if your autostart/alarm has a blinking light if that sits for like 2 weeks it is a drain on the battery and if its a weak battery that could be the issue.

 

Start by disconnecting the battery for a week to see if the battery is OK sitting that long.

 

Thanks for the replies. Pretty cold here now, so I'll try the suggestions when it gets a little warmer.

 

i doubt one measly LED at ~0.04A can drain a battery. I remember reading an article that the FHP's new Crown Vics outfitted with a plethora of LED lights all around can be left on for a week+ and the car will start fine.

 

Very true but his truck is not a new crown vic its a 97 and probably does not have the same electrical precautions. And if its a weak battery you never know. Either way it was just an idea.

 

with a weak battery it is possible, since our trucks have the ACC ports powered 24/7 as well