2002 3.0 auto T$C LX. Every couple of weeks battery is dead. Battery is ok. Is the IPM fuse box supposed to be hot on all fuses with key off? Really scratching my head on this one. Will be ok for couple of weeks and then dead overnight. Any known problems like this? I have disconnected the onboard entertainment and it runs off accessory plug when used other wise always unplugged.

 

perform a battery off draw test

 

To perform the battery drain test, you'll need some written resource such as a high school automotive text book or a decent shop manual. you will also need a decent quality DVOM (electrical test meter). once you have these components, you can analyze the situation more effectively

besides a typical electrial draw to drain the battery... here are some common causes for this issue:

hood, glovebox, or other light draining battery. those lights may not be noticed at all being on.
next common lack of battery maintenance. I had a lady that had this problem. using effective customer communications during the proceedure to verify the complaint, I determined her problem occured on humid rainy days. see the battery with a slime built up on top, when it was humid, a short circuit was created across the battery.
another issue was a bad alternator
additionally was an actual bad battery. it showed good voltage and did pass a load test...on the low end but in spec. but when I did a specific gravity test, one cell showed a bad reading
so inorder to properly resolve this issue, the internet isn't going to GIVE you an exact answer, you need to use a rational and pragmatic systematic approach in diagnostics

 

I've considered the lights as well. I have a good meter volts amps and the like. Pretty good at schematics and have the chiltons on the car. This one has me stumped on the every couple of weeks or even month doing this. Gonna put my head into it this weekend. Was hoping to get to work on my 66F100 that is my project.

 

Well, to pinpoint the cause, you'll need to journal and chart all the conditions in which the problem arose. Once you have established enough significant data, then you can predict when the event will occur so you're ready to take action at that moment. Then you just might catch the cause to resolve the issue.

additonally you never stated some of the conditions in which this occurs. like was the van sitting for any significant amount of time? is it consistantly occuring every 2 weeks to 1 month. who was driving just before the problem show?

Using SPC charting techniques, you'll have a better chance of pinpointing the problem.

 

How old is the battery???

 

It happens randomly, every couple of weeks or so. Sometimes after sitting for a few days but not always. 3rd battery about 3 months old. I've had the battery tested a 2 different battery/ auto shops. Last battery I put in another car and it is fine. I am wondering does anyone know if the entire fuse box is supposed to remain powered up or just certain fuses? My thought is some should only power up when key is on or in accessory position.

 

a wiring schematic is CRUCIAL to successful diagnostics. I am someone that knows if the fuse box is suppose to remain powered up, but it depends on what fuse block you are talking about since this vehicle has 2.

Again, if you were to chart the occurances of this problem, recording as much data as possible, you have a much better probability to pinpoint a cause. What you may think is random just may show a direct correlation to the problem at hand.

Don't be a bull in a china shop diving in throwing parts at it (like multiple batteries). using a rational, pragmatic and systematic approach to accurate diagnosis is the ONLY correct method to servicing and resolving this issue once and for all.

I can not emphasize the importance of using logical diagnostic methods to trouble shoot this issue

 

under the hood is the box I am talking about. Where is the other one? I have the wiring diagram in Chiltons. I know what you are talking about, I ruled out the grandkids pushing the overhead lights on, rewired the onboard video where ir has a pulg for accessory on it no more direct wired. Some times it sits and this happens or only after overnight. Nearly always after a overnight sitting. Never consecutive times tho. Altenator puts out 14 to 15 all the time. Once it is jumped off and runs a few minutes it restart just fine. I don't like throwing parts at it either.

 

oops, I was looking at a 2000 they have 2 fuse pannels. so you are saying that ALL the fuses in the pannel are hot at all times?

some day when I'm bored and have nothing better to do, i could go out to my 2002 town and country and measure all the fuses to see if i'm getting what you say having all fuses showing power.

I took a couple seconds to see the factory wiring diagram for the PDC fuse. for example 11, 28 and 33 should not have power with the key off