Dead battery
 

I went to start my car yesterday after it sat for about a half hour. Before I was driving for about 2 hours to different places so I started the car a few times. Well it wouldn't turn over so I called my friend to get a jump. It started right away and I let it run for about 20 min to let the battery recharge. Then it died out as I revved it up. So we jumped it again. This time it died out after about 30 seconds when I tried to drive it. Now it won't hold a charge at all. The only thing I did was take out the instrument panel because I'm getting a new gear in the speedometer. So I was driving with no speedo or tach or anything. I'm thinking that could have caused a short or something. Because I didn't do anything else to it. Any thoughts?

It's been a while since I've dealt with this, and I don't remember the years invoved, but on older Mustangs, disconnecting the harness to the instrument panel opens the circuit between the alternator and the battery, and essentially makes your alternator useless. Don't replace the alternator until you've reinstalled the instrument panel and seen if that fixes it. If it doesn't, then your alternator will need to be replaced. I don't think you'll have to worry about it, though, just put the dash back together.

Take care,
~Chris

Ok I get the instrument panel back on monday. I will let you know if that works, thanks for the help