2006 Mustang Electrical Drain Issue - Assistance Appreciated

Odd (to me; full disclosure: I'm a pretty fair shade-tree mechanic, but modern, computer-controlled electronics are NOT my strong suit!) issue with my wife's 2006 V6 4l mustang. It doesn't get used a lot in the summer and can sit for 2-3 weeks without even being started... The other day, went to use it, dead.... checked the battery, 2 volts, charged it, load-banked it and it failed... it was five years old, not a huge surprise. Replaced with a brand-new good quality battery... sat for two weeks while out of town, and.... dead; down to 3.5 volts.

Charged it and it started fine. Put the ammeter on it, and there's an initial draw of around 1.25 amps, which after 30 seconds or so reduces to a continuous draw of .1 amp. That seems high for a car "at rest, even a modern one.

I've physically disconnected all after-market accessories (only two) and the draw is still present. So... any thoughts? I know how to localize the issue, but time is short for the next few weeks, and I'm hoping that someone out here is TW land could give me some suggestions (on the electrical problem.... I get all of the other kind I need already!).

Thanks!

 

Pull fuses one at a time while watching your amp meter to try and narrow down what circuit is responsible. You can then determine what is on said circuit and clean contacts etc to narrow it down.

Was anything new put on that could coincide with this issue starting? Something older put on that may not be working correctly anymore that is responsible? Aftermarket radio, amp, etc? Some sort of charger?

 

Does is have the stock shaker radio? Back when I had my 2006 Mustang, I believe there were issues with the stock s197 shaker radios having continuous draw issues. I always made sure to turn off the radio before turning off the car. (I still do that in my Tacoma out of habit). Not sure if this will help, but that’s what I remember years ago when I had my 2006.

 

That's the problem; NOTHING has been installed in at least five years, issue has started in the last few weeks. The only two after-market items have been physically disconnected from power (and showed zero draw regardless). I'm familiar with the 'one circuit at a time' the problem is, I don't have a lot of time. Thanks!

It does have the stock radio; I'll definitely have a look at that tomorrow. Thanks!

 

The most common things that cause parisitic drains like this are glove box lights, trunk lights, underhood lights and vanity mirror lights. As mentioned, pull fuses 1 at a time to isolate the problem. It doesn't take that long to pull fuses.