Electric problem
Electric problem
Are you driving a Plymouth Fury? link
All jokes aside...
You shouldn't see anything much higher than about 14 volts anywhere on a 12VDC nominal automotive electrical system with the engine running. The only exceptions are HD and emergency vehicles - sometimes those are closer to 16V.
Sounds to me like your voltage regulator is pitching a fit - hence the high voltage in one spot. I'm unsure if the alternator bolted to your engine is internally regulated or if there's an external regulator somewhere, but I'd start with that and then worry about the other funky goings on after you solve that. You don't want to cook your battery or everything else with too much voltage.
In the meantime, give everything a visual once-over. Look for bad grounds, chafed wires and corrosion - eliminate any of these issues and take steps to avoid future problems.
Beers,
Matt
Ditto with the regulator. Also, if the diode trio is fried and letting too much AC voltage through it can play havoc with the electronics (radio, antenna, wipers). The regulator is an easy 15-minute job with just a Phillips screwdriver but the trio means the whole alternator has to go.
Take it to a place like autozone or wal-mart where they will test the battery and charging system for free.