1994 E320 Wagon - Won't Start
 

We have a sweet 1994 E320 wagon that has been driving well since we bought it several months ago. Today we were running around doing chores and on the last stop we made, when we started the car up, the air conditioning would not cool. We got home and my wife took the kids to a dance, and when she came out to drive home, the car wouldn't start. It isn't the battery, because all the lights work, and if I try to jump the battery, it doesn't do any good. I assume it is the starter, or some interlock switch, but is there a way to confirm what the problem is?