[Dagwood03]

i need some help folks.... i have a 2005 mustang GT with twins and all the goodies... obviousley with the twins its not a daily driver so heres the problem... when i set it in the garage for the week the battery goes dead... i charged the battery and i kicks right over runs fine run it around the block and run it all week and its fine but as soon as it sets a week it dies. it confuses the heck out of me cause i can set my turck for the week i drive the mustang and it fires right up... can anyone think of what may be drawing it down... i havent messed with the electrical system other than guages... and i know i keep the door closed and make sure the dome light is off... all suggestions will be appritiated

[bubbahotep]

You probably have a small drain from some computer or ignition component and unless you disconnect the battery you'll always drain it. I recommend a battery tender charger, keep it on there 24/7.

I have a non computer car with just msd ignition and a timing box and a brand new optimum yellow battery, close to dead after a week. If I disconnect it, it holds.

You could pull 1 wire from the battery and put an amp meter in series to see the drain. All multimeters have them, it'll read low but most likely shows something.

It is also possible the battery is bad and just can't hold it's charge unless used daily.

[T-bucket23]

More info is needed. Does it still have the stock computer and harness. What electrical modifications have been made if any.

If you have an amp meter connect it and pull fuses one at a time to see when the draw goes away. In most newer cars things systematically shut down once the car is turned off and the key is removed. You dont by any chance leave the key in the ignition do you

[75gmck25]

I also have a 2005 Mustang GT, and the most likely source is the radio if its a Shaker 500 system. This has been a problem with quite a few of these Mustangs, but Ford has never really provided a good explanation.

On my car I have found that sometimes when you shut off the car the CD part of the radio stays on. It must be powered through a separate internal relay. In a couple cases I have gotten back into the car and found the sound system was constantly shuffling the CDs, even though the car had been turned off for more than an hour. When I finally got it to reset to normal and stop shuffling, I had lost the clock time but still had my radio presets.

My solution - I have removed all CDs from the six disc changer and usually leave them out. Also, before I shut the car off I turn the radio off separately. This seems to have resolved the battery run-down problem.

I had one Shaker 500 radio and battery replaced under warranty because of this problem, but had to try something else when it went out of warranty.

Bruce

[vicrod]

Never heard of the twin option for the Stang. Is that twin turbos? What is it?
Could be draining the battery.

vicrod

[oldred]

Originally Posted by 75gmck25

I also have a 2005 Mustang GT, and the most likely source is the radio if its a Shaker 500 system. This has been a problem with quite a few of these Mustangs, but Ford has never really provided a good explanation.

On my car I have found that sometimes when you shut off the car the CD part of the radio stays on. It must be powered through a separate internal relay. In a couple cases I have gotten back into the car and found the sound system was constantly shuffling the CDs, even though the car had been turned off for more than an hour. When I finally got it to reset to normal and stop shuffling, I had lost the clock time but still had my radio presets.

My solution - I have removed all CDs from the six disc changer and usually leave them out. Also, before I shut the car off I turn the radio off separately. This seems to have resolved the battery run-down problem.

I had one Shaker 500 radio and battery replaced under warranty because of this problem, but had to try something else when it went out of warranty.

Bruce

You sound just like a Neighbor of mine because he has the exact same problem you have and he also has a 2005 GT. The suggestion to pull the fuses one at a time until the load disappears is about the quickest and surest way to find out at least what area the fault is in and that will make it much easier to locate the exact cause. Putting a trickle charger on the battery is not a good idea because it simply masks the problem and does nothing to correct it, not to mention the hassle of having to do it regularly.

[Dagwood03]

hey guys thanks for the help. i think im gonna mix and match advice and put on a battery cutoff first and possibly a battery tender too for security sake... and yes the twins are twin turbos... but i never disturbed anything electrical mocking them up... i think it maybe the battery. it is still the factory one... y change something that still works?

[oldred]

I think you will find the battery cut0off to be a big mistake because you will loose your settings every time you switch the battery off. Radio and clock settings are bad enough but the computer will dump all it's saved data, possible codes, etc and have to start out over again every time you switch the battery on.

[SSedan64]

5yr. old factory battery. I think you found your problem.

[oldred]

Originally Posted by SSedan64

5yr. old factory battery. I think you found your problem.

I didn't catch that part, bet anything that's the culprit.

[evolvo]

I had a car in the shop with the same problem, battery always going down. Unhooked the neg cable at the bat and put a test light in series. Probe in the neg terminal and clip on the cable. It glowed pretty bright. Started looking around and found the ciggy lighter was stuck in. Pulled it out and problem solved. Moral: it could be something really easy!

[oldred]

Originally Posted by evolvo

I had a car in the shop with the same problem, battery always going down. Unhooked the neg cable at the bat and put a test light in series. Probe in the neg terminal and clip on the cable. It glowed pretty bright. Started looking around and found the ciggy lighter was stuck in. Pulled it out and problem solved. Moral: it could be something really easy!

I did the same a couple of years ago on a Ranger truck and it too was the lighter but in this case it had the burned up remnants of a small safety pin in the bottom of the lighter socket. On two other occasions I have found the glove box light was failing to go out when the door was closed and that little light would pull the battery down in about 3 to 4 days.