Hey all!!! been a while since I was last here.

OK, let me tell you what's going on.

I have a 1997 F-150 with a 4.6l, 4 speed auto. No power anything except cruise and A/C. Here's the problem. Every once in a while, the battery dies. Usually overnight. At first I thought it was a bad battery, as it was a few years old. I bought a new NAPA battery with high CCA's. Didn't do the trick. I put the charger on it and half an hour later, it's good to go. Fires right up and it's good for some time. Other times, it's a daily thing.

Question... Could it be the alternator or maybe the GEM module staying energized after the ignition is turned off.

A friend of mine has the exact same problem with his 2001 F-150. He solved the problem by installing a master switch. But, it doesn't answer the question as to why this is happening.

Any help would be greatly appreciated.

Joe

 

Somethig is staying energized for some reason. You don't have any aftermarket lights, stereo, etc. that could have wiring issues, do you? When you park the truck for the night, are you sure all the lights in/on it turn off.

 

Amp meter the battery after shut down to look for any draw. If you have draw, pull fuses one at a time until the draw dissapears. That will be where you need to look next to see what is actually staying on since most fuses supply power to multiple items. I've seen wiper motors hung in an ON state even though the wiper switch is turned off and the wipers are not moving. Also have seen fuel pump relays hang in the energized state.

 

Thanks for the replies...

I have four lights on the headache rack. They are all disconnected. A remote starter which I also unplugged. Other than that, all factory equipment. I live outside of town and it's very dark at night. One of the first things I did was look for lights staying on.

If I do an amp draw test, the computer is constantly drawing on the battery, which is normal. How much amperage should the computer pull?

I have been disconnecting the battery at night but that defeats the purpose of a remote starter on these cold -30 deg. mornings.

 

KEEP-ALIVE circuit normally will only be about a .125 amp draw.