1999 Chrysler Town and Country Starting trouble

Sometimes, when I try to start the van, the odometer lights will not light up. This is my only warning that it will start and immediately shut off. If I continue to attempt to crank the vehicle, it will do this for about 3 times and then it will not even turn over. The battery will still turn on all lights and operate everything in the car but it will not crank. Trying to jump the car off does nothing. The battery registers good. It will fix itself after several minutes or hours and will start fine. Then, with no warning, this happens again. All fuses are fine as are the relays. When it cranks, it runs fine. It has recently begun to do this more often and take longer to "fix itself". Because it seems to repair itself, it never has done this by the time it arrives at the shop and the mechanics cannot seem to diagnose the problem. It seems electrical but I am at a loss, just very frustrated. Thank you for any help you can offer and I appreciate your time.