I have a 2003 Ford Taurus, and noticed the battery draining at progressively-shorter intervals. It now drains to where it won’t start, within just a couple hours if the car is sitting with the battery connected. I attached a multimeter between the negative battery cable & post, and looks like there is a 1.1 amp draw. I started pulling fuses one-by-one, and found the following fuses where the results changed:
Below, I’ll list what the draw dropped to on the multimeter after removing the fuse, (the fuse #), and what the fuse chart said it covered. All 3 fuses were under the dash:
0.06-0.46 (F2.16)- Generic Electronic Module (GEM), Remote Climate Control (RCC) Module, Instrument cluster, Multifunction switch, Integrated control panel. This showed a 0.06 the first run-through on testing, and I checked it multiple times. After going through all the remaining fuses, I came back to this one, and removing it only lowered the draw to 0.46. (Sub-question - why would this change so much, when all the other fuses had repeatable results?)
It looks like F2.16 would be the place for me to start. Is that a correct assumption, or does it look like there are multiple issues at hand?
It looks like there could be any number of components attached to that fuse. Is there a resource which shows me everything on that fuse beyond the generic list I found?
Is there a way to somewhat-easily disable certain items that I’ve had trouble with in the past? Example could include my radio, which eats CDs, or the glove compartment which I thought had a light, but can’t locate it since the glove compartment fell apart.
What in general is the methodology for testing beyond here? I found a video on Youtube, where the guy started poking around with an alligator clip/wire combo and ended up snipping wires on a hunch, but I could see that going badly quickly.
The door was open when you did this check, correct? If so, did you give sufficient time for the electronics to stabilize? When you open the door, courtesy lights turn on and a few other things might activate that are a transient current draw. After some time, those systems would shut down. That would be the time to run this test. Your description did not say that you waited for all the door activated systems to shut down, even though you may have. If you didn’t wait long enough, and I don’t know what time that is, the current draw could be related to jus opening the door.
Agree with JT here. You need to be careful with the GEM, It can keep things alive when the doors are open and even after they are shut for a short while.It keeps things alive so you can power up the windows, light the headlights for a moment and others. Be sure to close the doors and wait for things to time-out.
I am a bit confused by your current draw numbers. They are the reading when that fused was pulled? So 0.82 amps on F2.10 was the draw even after the fuse was pulled? I shall assume that based on the rest.
Seems like 1/2 of the draw is F2.26. 1.1 minus 0.66 leaves 0.44 amps? That is way too high. Seems like one of those lamps is still on. Check to see if the bulb is hot when you first open the luggage compartment and interior lamps. Pull the hot bulb and re-test.
That is the path forward on each of the fuses. Start unplugging each component on that fuse one by one. A short in the GEM could easily pull enough to kill your battery.
I had an instrument cluster that had a bad trace that would kill my battery every 3 days on a car that sat quite a bit.These things can be a bear to find! Good Luck and post back with what you find.
I would disconnect the negative cable at the battery and let the car sit overnight. Then, the next morning, reconnect the battery. If the engine won’t crank, you have a bad battery. If the engine starts right up, then you have a current draw when the car is off. Check for a light that stays in when it should be off such as the light in the trunk or glove compartment. I once found a sticking light switch in the console of an Oldsmobile my parents once owned. A couple of different garages looked for a parasitic draw and couldn’t find it. I checked the car at night and saw a little head of light around the lid of the console.
I’ve had two over the years. One was traced to a rusted door handle switch that turned the interior lights on when you pulled on the handle. The interior lights would just go on by themselves when you weren’t looking. Found it by going out to the garage one night and the lights were on. The other was to the electronic level control module. That one was very intermittent. Check once and it was ok and a few minutes later it was activated while it sat. Both drained the battery in no time and for both I just disconnected and left it disconnected. No point replacing a $300 electronic part on a 15 year old car.
Good luck though. Persistence and step by step elimination.
This kind of problem used to be easier to solve in days when cars were less complicated. Now-a-days we all like the electronic gadgets and gizmos, but the downside is that each of those gadgets and gizmos has a computer looking after it. Those computers have a “sleep” mode they enter when not needed like when the car is parked and engine is off where they draw very little current, but if something happens where they wake up, watch out, it’s current-draw city. So something or another is waking those darn computers up for some reason, or never letting them go to sleep in the first place.
If the car is parked in a dark place, take a look at it during the night several times over the course of the evening, any lights on? Esp check the interior lights, the brake lights, and the dashboard lights. Don’t open any doors or even touch the car when you do this. Listen for any sounds too, like HVAC vent and blend door actuators moving, trying to find their home position. If there are any lights hidden from view like in the glove compartment, or in the trunk, remove those bulbs and see if that helps. One common cause for this is an intermittent door open/close switch. They can develop a hair trigger and switch on and off just by the wind blowing on the door, or a big truck going down the road. That makes the car think someone is getting inside and going to start the engine so it wakes up all the other computers. Don’t forget the trunk and hood, if they have switches. Switches in the brake and accelerator pedal could be suspects it too. Another common cause as reported here are stereo systems and security alarms, especially if they are aftermarket.
As mentioned above, there’s usually fairly large current draw for a while after you park. It should go down to the 50-100 mA range after 30 minutes or so.