Hi all, first post here. I have a 99 XJ 5-spd that has developed some strange electrical gremlins. When I go over bumps, the dash lights and radio will flicker on and off, and sometimes completely go out. When they go totally out, I lose AC and my speedometer. My thinking is they're all going out at once, just it's only noticeable when they're out for a longer period of time. To make things weirder, sometimes when I pull up my parking brake, it causes everything to go out completely, and all my idiot lights come on. A few weeks ago I lost everything for a good hour or so, and in that situation my headlights were way dimmer. Then randomly everything just popped back on. I feel like I'm losing my mind. Anyone dealt with anything like this? Any insight is greatly appreciated

 

It first I was going to say the two connectors on the back of your instrument cluster aren't seated properly, but when you mentioned the headlights and other things I began to think on or more of your grounds is acting up. I'd start with the battery terminals/leads and go from there.

 

Charge the battery,
Disconnect the Pos cable from the battery,
Rig an DVM (set to amps) between the battery and the POS cable,
pull and put back fuses one at a time until you see a drop in amps being drawn.