Battery Drains While Car Is Parked....

[ninja_rabbit]

I did a search and couldn't come up with anything comparable...

For the last month or so, if I park my car the battery discharges itself. At first I thought it may be the battery, so I put another one in. It was good for about 5 days and tonight I went to start the car, and no-go. Alternator shows 14.4 volts. Battery discharges after about 6 hours. No aftermarket accessories are on the car except my Sirius satellite radio, which draws practically nothing. The only thing I can imagine drawing is the factory alarm, but it should also draw hardly anything. This also seems to be somewhat of an intermittent problem. I can go a few days without the battery discharging, the all of a sudden it'll do it for 2 days straight, then be fine again for a couple of days.

Now, here's one thing I did notice: The posts on the battery are clean, and tight... but on the positive cable there is a smaller red wire tied into it. This wire has been cut off. Now, my question is, was this wire put on after the car was built, or is it supposed to be leading to something? Do all gen 3 Tauruses have this smaller wire running off of the positive cable?

Car is 99 Taurus with 3.0 Duratec.


Thanks in advance.

[redtires]

Hmmm...that is odd. The only thing that I can think of is that (and it's blatently obvious) is that there is a drain somewhere in the factory harness. The only way that I know how to find it is to literally track the sucker down. True, your satalitte radio should drain virtually nothing, I've left mine on for days by accident and still had no problem. As for the extra wire off the batt....my '06 has one too, although I'm not 100% sure where it leads to...and quite honestly it's way to cold and dark to go out and check right now...lol. But yes, I believe it is supposed to be there on your '99 as well. A friend of mine had a similar problem on his eclipse, he had to take it to a shop and have them find the drain for him. You don't have anything else aftermarket, at all??

[ninja_rabbit]

Absolutely nothing aftermarket other than my Sirius. It has factory alarm as stated, and factory 6 disk cd changer in the back. If you do figure out what that extra wire is for please let me know.

Thanks.

[CustomPerfSys]

my 97 does not have it. but what i would check is some of the chassis grounds, make sure they are good, if somethings not grounded properly, you could be leaking voltage. if you drive around for a good long time does it fully charge? i would test that to make sure the voltage regulator isnt shot or anything. a good 30 minutes of highway driving should fully charge the battery.

[ninja_rabbit]

Ya DragonKnight, it fully charges. If I drive it for 20 or 30 mins, and shut it off, it starts right back up. The starter turns like crazy. It's only after it's been parked for a couple of hours.

[the_intimidator_02]

Just something to keep in mind, driving you car for 30 minutes does not fully charge your battery. A dead battery requires 12-14 hours of charge to become fully charged. Driving the car for 30 minutes will only put a little charge. The alternator is only meant to maintain a charge in the battery. Therefor if the battery is low on charge to begin with the alternator will not add much more to it. If you really wanted to charge the battery fully with the alternator you'd have to take a 12 hour road trip.

[shoz123]

I had this problem on my '97 and it turned out to be the football panel. I even put in a used one but it too had a 0.5A draw all the time.

Finally put in a third used one and it is now OK.

You need to hook an amp meter up between the battery negative post and the ground wire. Set it on amps and see what the draw is. Should be under 0.05A. If it is higher first wait 15 minuts to see if the automatic stuff times out as some modules will stay active after the door is opened or the key is cycled.

You will probably have to pull the interior lighting relay to kill the lights.

Then start pulling fuses until you track the circuit down that is causing the draw. It can be pretty agravating but if you methodically go through everything you will find the wire that's causing the problems.

Probably need the wire diagrams too. www.fordcds.com has the Ford factory manuals on cd for free.

[ModemJunki]

Don't forget to check and see if the trunk light stays on. (Do 99's have a trunk light?).

[bob woods]

Its been my experience that the small red wire that ties to the Positive battery terminal goes to the alternator output, either to the back of the alternator or to the relay box through a fuse. In my case on a 97 Taurus it goes through a 175 amp fuse to charge the battery.

[RickMN]

The wiring diagram shows two red wires coming off the + batt terminal. The big one goes directly to the starter. The 2nd one goes to the Mega Fuse (Right side of battery juntion block). After the mega fuse, an orange/blue and yellow/wht wire goes to the alternator.

As for battery drain, here's how it's diagnosed. You will need either a low amp clamp meter, or a digital multimeter with an amps featuer. The clamp meter is easiest. You clamp the meter onto the negative battery cable and wait for 3-5 minutes after the car has been shut down. At that point, you should see a significant drop in millamps due to computer shutdown. After shutdown, you should see no more than 50 milliamps. That power usually goes to the clock in your radio and any keep alive memory in the computer. If you see more than 50 milliamps, you've got something that's not shutting down. To find out what that something is, remove 1 fuse at a time until you see a drop in current draw. You should also pull each relay to check for the same drop. Most of the time, an intermittant problem like this is caused by a gremlin relay.

Another way to check is to attach the low amp probe and smack each relay with the handle of a screwdriver. If the current drops, you've found the bad relay.

If you have to use the digital multi-meter, you'll have to hook it in series with the negative battery cable.