Before you start taking them apart, you should measure the resistance with an Ohmmeter. Measure first!!!
In fact, it is unlikely that you should remove the drivers given the description of your problem. If there is a connection problem, it is likely on the binding post, not on the driver(s). There is one binding post, and four drivers, so it would have to be something that affected all drivers. Plus, you really don't want to mess with the trim rings unless you have to.
From your description, it may be that the wire from the binding posts to the crossover became disconnected. If so, looks like you can remove the terminal cups with a couple screws and get to the wires that way.
But, measure first before you start to tear into these. And, get some help.