Dead battery - get into trunk?

I had a totally dead battery this morning after not driving the 2015 GT Convertible for about three weeks. First off, is that normal? I've had no problems up until now leaving it for a couple weeks at a time. I just ordered a battery tender (this guy: https://www.amazon.com/Battery-Tend...492744482&sr=8-5&keywords=battery+tender+plus) for when I won't be driving it for a while, but I thought a few weeks in a garage in a non-cold climate would not be enough to totally kill the battery. I mean I can't be sure one of the dome lights wasn't left on, but I guess I assumed the car was smart enough to turn off the dome light after some period of time.

Also, my jumper cables were in the trunk .... which I couldn't figure out how to get to with a totally dead battery. Is there a way? I was able to get into the car with the key but the trunk release button did nothing without power.

Finally got a jump from a neighbor, but his smaller car took a while to get enough charge to actually start the Mustang. There was a lot relay clicking and lights flashing the first few times we tried before we gave it about 5 minutes and then it finally fired up.

There is a lock on the Driversside of the back seat. It is located between the cushion and quarter panel. You use your glove box key or the emergency key in the fob to open the trunk.

Pretty sure can access the trunk by pulling/folding down the back seats

Not on a convertible

ohhh crap 10/4 mybad

The battery should start the car after sitting for several days and probably several weeks. Mine occasionally sits for a week and it starts right up. You can also install a battery switch in the hot lead of the battery. They're all over eBay and Amazon for cheap. I bought a portable emergency start battery that I hope I'll never have to use.

Do you have the Enhanced security alarm? Those interior motion sensors eat up a lot of power. If I'm going to not drive the car for a while I set the alarm to perimeter sensors only.

awmustang said:

Do you have the Enhanced security alarm? Those interior motion sensors eat up a lot of power. If I'm going to not drive the car for a while I set the alarm to perimeter sensors only.

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'verts come with this as standard.

peetucket said:

I had a totally dead battery this morning after not driving the 2015 GT Convertible for about three weeks. First off, is that normal? I've had no problems up until now leaving it for a couple weeks at a time. I just ordered a battery tender (this guy: https://www.amazon.com/Battery-Tend...492744482&sr=8-5&keywords=battery+tender+plus) for when I won't be driving it for a while, but I thought a few weeks in a garage in a non-cold climate would not be enough to totally kill the battery. I mean I can't be sure one of the dome lights wasn't left on, but I guess I assumed the car was smart enough to turn off the dome light after some period of time.

Also, my jumper cables were in the trunk .... which I couldn't figure out how to get to with a totally dead battery. Is there a way? I was able to get into the car with the key but the trunk release button did nothing without power.

Finally got a jump from a neighbor, but his smaller car took a while to get enough charge to actually start the Mustang. There was a lot relay clicking and lights flashing the first few times we tried before we gave it about 5 minutes and then it finally fired up.

Click to expand...

is their not a button near the glasses pocket? to open the trunk ?

I retired from the company that makes batteries for Ford and they required a 45 day test to pass, so you should never have a problem in less than 45 days unless something is wrong.

Why do you need to get into the trunk..?

Even though the battery may be there, isn't there a terminal under the hood still...?

w3rkn said:

Why do you need to get into the trunk..?

Even though the battery may be there, isn't there a terminal under the hood still...?

Click to expand...

That was to get his jumper cables. Also, the battery is in the front.

Thanks all. I found the manual key latch to get into the trunk (between back drivers side seat cushion and quarter panel, just behind the back cushion). I did search the manual first before posting and didn't find this. As noted above, even though the battery is under the hood, the jumper cables are stored in the trunk.

I didn't think about the perimeter alarm, but I will turn it off now for extended non-use (really don't need the alarm in the garage anyway). The car was definitely sitting for less than 45 days, it was probably 25 days or so (with all alarms on). Voltage on the gauge when driving after the jump yesterday and today was between 13.5 (idling) to about 14.5 (on the highway), which seems to suggest the alternator is fine, right?

It is possible the passenger dome light was left on when it was parked, since after the car was jumped, I saw it was on when I was driving with all doors closed. If there isn't some auto-off feature for the dome light when the engine is off, that would certainly have killed the battery.

Cross my fingers - so far no problems yet, but will put the battery tender on it tonight after it arrives from Amazon to top off the battery.

I had mine do the same, sat for 3 weeks and I had forgotten to put the tender back on :headbonk:.

When I stopped at the local dealership before I bought my car, the first two Mustangs they grabbed keys for were both deader than a hammer. The salesman even said, "if these cars sit for a couple of weeks they kill the batteries."