Checked tbc, tbc2, tbc3 fuses in engine compartment. All are fine. The battery seems to have plenty of juice, as it starts the engine without any problem whatsoever. Yesterday afternoon the gauges started going haywire - ABS light, security light, check engine light, gauges not working at times, then coming back to life, etc. I've had similar problems in the past, but had it repaired recently (seemed to be bad/loose ground). Had been working fine for a few months, until yesterday. The gauges and dash lightes indicated above would come and go as I drove, speedometer, gas guage, etc showing nothing, then reading normal - in and out in and out - drove some 400 miles this way. Trying to get home tonight travelling at freeway speeds with the gauges and dash lights continuing to do what they had been since yesterday afternoon. Had not used the headlights a whole lot until tonight, and had been driving for an hour with headlights on and radio. All of a sudden, without any warning, going 80 mph, all lights (including headlights) went out. I managed to tail another vehicle for about 10 miles to get to the next town and gas station where I am now.
The dome lights do come on sometimes, until something else is turned on (or attempted to turn on) then the dome lights go out again.
By the way, I stopped at O'rielly auto parts yesterday afternoon after the gauges started flaking out. They check the battery and alternator in the vehicle. Both said OK, and it showed 14.4 volts at the battery with vehicle running, although the charge indicator gauge in the dash was only showing 9-11 volts. It had been showing 14+ volts until the moment the gauges started freaking out yesterday.
One more clue - when done at the job site today, the van didn't want to start. It turned over fine, but wouldn't start. After several attempts and pumping the gas pedal as I cranked it over, it finally started and we drove for about 90 minutes before these issues started.