Just today I went to start up my mustang since its been sitting for a week with no activity and it couldent fire up. Seems my battery is dead, only the problem is the battery is just a few months old. No i didnt leave the headlights on, infact I still have enough power to turn them on.

So something might be draining it. The only thing active during the week would be my car alarm/immobilzer which iam guessing takes very little power. Funny thing is I was able to disarm it but now it wont rearm now. The only thing I may have left on was the windshield whipers set in the on state when I turned off my car. Does anyone know if that might have slowly drained my battery?

 

Have the battery tested even tho its new still could be bad also could try a volt meter on the - wire if anything shows up then start pulling fuses tell it stops then find out what all is on that fuse.I had a mazda do the same thing to me if it sat more then 4 days it wouldnt start turned out it was the horn relay so anything can do it.

 

you better off measuring amps for this. not voltage.
switch off everithing in car. disconnect mattery minus.
Connect ampmeter between the battery minus terminal and the loose cable that was there before as in

(battery - terminal)----AMPMETER----Loose Cable

again. in between. not parallel. measure how many amps that car is pulling. I'll veryfy when home later what mine is pulling.
But my guess is only the clock should run which should be about 50 or 100mA (i'll check on that). Anything more check on the fuses as in above post.
Get rid of one fues and see if that brings it down. If no, try next fues. If yes check on wiring guide what ios hooked on that fuse (radio, courtesy light, trunk compartmenr light ... ect ) to find the culprit

Kalli

 

Have the battery and the alternator tested. If anything, get a better battery, perhaps an Optima. I love my yellow top in my truck, and depending on the application in my mustang, I plan on using one there too.

 

I hate being in the situation your in. Its not that it hard,. its just one big headache pulling wires until you find the culprit. Good luck my friend [&:]

 

As Kalli stated, the only way to isolate a drain is to use an ammeter installed in series with the battery cable. I would however suspect a weak cell in the battery you've recently replaced since you've changed nothing is in your cars' configuration lately.
Jim