My gauges were going out intermittently on my 97 Sahara. Some times they worked fine but then I'd park the TJ come back an hour later and they'd be out. I had the dash opened 5 times in 2 weeks trying to figure out why. With the gauge cluster removed I troubleshooted the pig tails and nothin. The pins inside the plug all seemed to make god contact and I added in some dielectric grease just to keep things nice and dry.
Then, the blower motor stopped responding. No fan whatsoever. The strange thing was how temperamental they all were. Lights on, fan worked. Lights off, tach works. And then nothing. Oops tach is working, no it isn't. No pattern to help diagnose.
I removed the glove box and switched on the fan. The relay next to the fuse block began making a weird buzzing noise. Upon closer inspection I noticed there was some dried red mud on it. This was the previous owners 17 year old son's mud bogging handiwork. 2 years since purchase and that dummies trip into a mud hole is still punishing me.
I removed the relay and emptied 1/3 of a bottle of electrical contact cleaner into the relay plug (pigtail whatever you call it). Some reddish muddy water emptied out the bottom. I allowed it an hour to dry and lo and behold everything works fine.
Will update this post if anything changes.
Thank you to everyone on here for helping me out along my TJ journey. 2 years in and I still feel like a newb!