I have a '90 lx, and Im not sure if this is related but three weeks ago I changed the plenum gasket. The next time I drove it I noticed that if I pushed the window switch after the windows were all the way up or down the battery light would flash and the lights would dim. It seemed to keep wanting to do this. A couple days later my battery was dead, and would randomly be dead sometimes when I would go to start it. I checked the alternator and it was putting out over 14 volts and I checked the battery over a period of time after the car was off and it held charge. One or two days when I was driving the guages would drop and pop back up when I would hit the brakes, and the radio would die and turn back on. A couple times when I have turned it off the black box under the passenger seat(looked in my book, dont know what it is) starts ticking kind of like a clock for about 30 seconds. The problems werent consistant, and then went away for a week or so but came back today. Any ideas? Thanks

 

That box was still ticking an hour after I turned my car off. I removed it and it says its the belt warning control.

 

Sounds like your alternator to me