I just thought of how I might have killed it! I washed and degreased the engine bay yesterday, but I put a plastic bag over the alternator just for safety. It still got a little bit in it, but not a lot. This happened in the morning and the car was fine all day, so I don't know if this is the culprit or not. Would water have a huge effect on the alternator anyway? Judging from the position of it, it'd quite easily cop a bit of water from underneath on a wet day.
1992 AXII Telstar TX5 Ghia
121kW 2.5L DOHC V6 in a car that weighs 1100kg's and looks like a 4 banger from the outside......SLEEPER!
1988 EA S Pak 3spd CFI.....Soon to be a 250rwkw HSV eating machine.