Check all your connection points (wires) to make sure somethingÆs not touching metal. Others have had this problem and research suggests that bad soldering on the instrument panel. Anything electronic is not fun.
A second theory that I have heard on the 95 YJ's (a year prior to you) is that water gets in under the dash. Some had the windshield molding replaced but others say that isn't the problem. There have been reports that the vent near the hood, right above the cowl on the outside of the jeep is where water is coming from. When it rains/gets washed/gets really wet; the water comes through the duct work and into the dash. Have you noticed moisture?
If moisture is present, it might be worth a peeksie. There is approximately a 1" hose located near the center of the firewall in the engine compartment. This is a drain for the vent/cowl that is located between your hood and windshield. Take a screwdriver and clean out all debris. The end of the tube may be pointed with a slit in the end; this is where the system starts getting backed up if junk is in it, and that is where moisture is coming from that *could* be causing your problem if its not draining properly.
I am told by a jeep mechanic that everything grounds to the dash and you can literally take something out like the speedo gauge and put it back in and it will effect something; everything has to be grounded perfectly. So again, check your connections. There is a guy that has a 97 TJ with the same problem as well. He had it fixed once, but as soon as he tried to put the dash back together, it blew the fuse again. I'm thinking something is pushing on this terminal block thats back in there, and shorting out the wire going into it. Find that wire and try to bypass the current wires that are in there.
Another thing I've heard is that there is a TSB, Technical Service Bulletin, out on this. Not really sure how to check for sure (other than going to the dealer)...maybe they'll cover it under a TSB.
Report back... I'm interested. At least if anything this will give you a few things to chew on. Cheers. <img src="/forums/images/graemlins/cheers.gif" alt="" />