AC generators can fail in a number of ways. Did they say what was "going bad"? If a diode fails you will only be able to get one third of the rated output current, but the voltage "ripple" will be very high. That terribly unsteady voltage can interfere with sensor signals and computers and cause those computers to do weird things. To prove if that is the cause of the running problem, disconnect the small wires from the back of the generator, then drive the vehicle a short distance. If it runs fine until you reconnect the generator, it could indeed be the cause of the running problem.
If the brushes are worn, they could be making intermittent contact. That would cause the generator to stop working completely once in a while. The lower system voltage could contribute to running problems but it's not as likely to as the failed diode.
Saturday, July 9th, 2011 AT 12:34 AM