looking for info on ground locations

So, I eliminated one bad ground last week that was affecting my headlight harness. Nothing else was affected at that time. That's been fine for a few days, but today I turned on my rear window washer/wiper and heard a click. Suddenly I didn't have:

-front and rear wipers
-turn signals
-headlights
-stereo
-blower motor
-power windows
-the Airbag light was on in the dash too. Not sure why.
-brake pedal made a click sound every time I pressed it. Don't know if
they worked or not, because I was driving.

So, I went out and tried to recreate the problem but no dice. It all seems to work fine now. Didn't bother checking fuses, but how could it be any of those if it's working now? I jiggled all the wire looms we looked at before, and the ground screws we cleaned up and fixed are nice and tight. Anything else I should try?

The problem has either become more widespread and was only temporarily fixed, or a different problem has reared its ugly head which affects a lot more stuff. Thanks in advance.

Can anyone tell me where the ground locations are for these? Most good manuals have them, but my manual is garbage.

Here's the thread about my headlight issues, which may or may not be related at this point. http://naxja.org/forum/showthread.php?t=1004711

I think there is a ground wire that is bolted to the center of the firewall in the engine compartment. This is the main ground for the instrument cluster. check that. I ran a wire direct from my Batt to this point and that solved alot of strange things on both of my XJ's.
Lardod