Okay guys...I've got a degree in EE and I feel like all my money on college (well, the military's money on college) was wasted as I cannot, for the life of me, figure out what my 98 Expy EB 4x4 is doing!!!

Started Sunday night after the superbowl. My wife has 22" wheels on her Expy and the neighborhood kids love to break into it...they broke in that night and stole the monitors out of the back of the headrests, the playstation (disconnected the inverter) and vandalized the headunit and the lcd monitor in the dash (however both the headunit and the dash monitor still have power to them and are not acting like the circuits are flaky).

Monday morning, my wife started the truck to warm it up to go to work....she came in and when she went back out, it was off. I assumed the battery had bought the farm, so I purchased a new 850cca replacement from Autozone (house brand). Tuesday she drove the truck to town (about 12 hwy miles) without incident. She said when she got into town, the windshield wipers started working slowly and the blower started blowing weak. After a while (she wasn't watching the dash volt gauge) all of the gauges went to 'off' position and a beeping noise (like the 'key in ignition/headlights on' beep) kept going off. Then it ran out of enough juice to power the ignition system and died.

I assumed it HAD to be the alternator now, so I purchased a new alternator from Autozone (house brand, but I assume new..not rebuilt) and installed it. The truck started right up off of a policeman's jump pack and I drove it about 15 blocks before it began giving me the same symptoms. Volt meter in the truck (with NO accessories on) show about 8 volts. All blowers/windshield wipers are obviously not running on full voltage.

So I parked it and got a multimeter...here's the kicker....when checking the battery at idle...it shows around 23 to 27 volts!!! However, after letting it 'run down'...to where it doesn't even have enough amperage to engage the starter solenoid, it STILL shows 20-some odd volts!! Like the regulator is shot. Granted I could have gotten a lemon of an alternator and the internal (I assume) regulator is bad...BUT...it's showing the same symptoms that the old alternator showed. Oh yeah..when we got the new alternator, and they tested the old one....it showed it was only putting out around 12.6v on the test machine (no indication from the salesman of a regulator failure).

Today a freind of myne has been checking things and he's told me that after putting a charger on the battery...now the truck doesn't show super-high voltage anymore when it's running...but that the alternator is obviously not charging the truck anymore, as after he gets it started, he can watch the voltage trickle down as the truck runs.

Any thoughts? I'm ready to find the kids who broke in and the idiot who engineered this truck and spend some time in a 'conference room' with them all.

The 'hopper

 

I think during the vandalism, some hot wires were probably shorted to ground, and now you have a fusible link burnt open under the hood. Check for continuity between the output wire of the alt, and the battery. It either has a fuse or a fusible link, and it sounds like it's burnt open. This would explain the alt not charging, and also explain the 27 volts, since the battery is the only thing that holds the voltage down in an automotive system. The regulator tries to reg the voltage, but it can do only so much if there is no load on the alt output wire.