I have a crazy problem that just started out of nowhere. Here are the symptoms. 1989 surburban. New engine, trans, radiator, thermostat, waterpump etc...all new. 1) Last night when I turn on the headlights, the truck died...like shutting off a light switch. No CEL illuminated, nothing. Radio and heater fan still work, but headlights and CEl and other lights are dark. 2) When this is happening I can still start the truck as long as I keep the headlights off, but it seems to start hard and if it is cold I need to keep my foot on the gas to keep it going (TBI engine). Eventually I tried turning on the headlights..no problem...seems to have fixed itself. 3) Another symptom possibly related or not. My coolant temperature gauge does weird things. Goes all the way to 230, then back down to 210, then to 180, then to 210 for a while, then to 180, then slowly climbs back up to 230. Could this be caused by an electrical issue? 4) I also notice sometimes I seem to lose my charging system, almost an audible "click" and my voltmeter drops to 12, headlights go dim etc...then a few blocks later..."click" everything brightens back up and I'm back at 13.2 V?? This does seem to be only when my headlights are on....I think...but I'm not sure. Any ideas??