Hello all you experts out there. I got a little problem with my Mustang that has been slowly developing. It started awhile ago when the car would not hold a charge after it hadn't been driven in a few days or the weather dropped really cold. (I live in New York.) Then the fan switch on the climate control settings would only work on the highest setting. Recently, the car won't even hold a charge overnight so I've had to use a portable battery to get it started. Today, I took it out for a little spin and mid-trip all of the dash lights suddenly came on, the car sputtered, and the then the theft light started flashing for the entire ride home. (Luckily it didn't stall out or anything.) When I attempted the use my keyless entry to lock the car it wouldn't even recognize it. I checked the obvious things like replacing the battery and checking all of the terminals for corrosion and everything looks good on that end. Does anyone know where I can start for troubleshooting it or should I just take it to the local dealer?
On another note, that may or may not be related, the brakes seem awfully weak too. I have to push it all the way down and the Mustang has nowhere near the stopping power it had before. I checked the pads and brake fluid and they check out ok as well.
Thanks for any advice that anyone can give me, I could really use it right about now.