This problem was very minor at first just increased sound volume on the radio. It progressed until the air bag light started to flash, the engine would slow due to maxed out alternator, then the transmission would shift out of overdrive due to the increased load, sometimes the O/D off light would come on and even the engine light. It had three alternators and two batteries in the last year and a half. Mazda changed the EGR valve, (could have been a false error from the voltage surge), and said they changed the intake manifold but this was a lie. The wiring is a nightmare to fix. The diagrams from the library show color coding that does not jive with the wires I see? There is nothing stamped on the connectors to say what is what. I spent four hours trying to figure out where the wire that "burned" went to in the fuse box and finally disassembled it to look at the "land patterns". to see where it went. I love the design but they sure don't expect anyone to fix it. The connectors were fine once I cleaned the "burned grease" off. Glad I didn't have to pay someone to fix this. Ended up with Two meters connected to the car while I drove and she monitored the result. Voltage went as high as 19.5 volts when it failed. Suspect it was graphite grease causing a short to adjacent wire or a high resistance in the Alt. control wire?