I discovered a wired electrical occurrence which I believe may be the cause of a shorted/failed battery. I store my 'stang in the winter months with a basic Sears (Shumacher) Battery Maintenance Charger. I leave the charger on throughout storage. Typically, the charger lights will alternate from green to yellow showing a discharge/recharge operation. This evening, I went out into the garage to find the charger green light on constant while the yellow light was flickering rapidly. the car's right taillamp and left reverse light were on. I opened the door to find the battery completely dead. Unplugging the charger stopped the rear lamp illumination. Could the charger be back feeding through the lighting system to cause these rear lamps to illuminate?..any damages do you think?

 

Assuming the battery charger itself didn't fail, I suspect it's just the battery and the issues with the tailights were due to improper voltage from the charger. Personally, I don't like leaving the same battery charger that I use for normal battery charging on ANY battery for chronic time periods (I charge deep cycle batteries weekly and marine cranking batteries about monthly) unless it's of very high quality (and expensive). When I used to store both Stangs for the winter, I used Battery Tender brand trickle chargers.

Pop a new battery in and let us know if she straightens out.

 

Thanks Nuke, I was on the fence about the battery. It's a Motorcraft which I suspect was replaced when I bought the car used (summer 2008). Battery life varies, but past (3) years, replacement should be contemplated.
I borrowed a small battery charger from work, hooked it up and got the same condition (backfeed through rear lighting). I will look into a replacement battery first of the week.
Any suggestions about a replacement? I usually go with OEM, keep maintained, and get good service life, but would consider others....

 

As much as I prefer Interstate batteries, I went ahead and put in another MotorCrap battery in the wifes '06 V6 about a month ago, simply because the dealership is close to where she works and her car was dead at work one evening. Pricey but convenient.