Explain how a fuse can be blown but a new generator works at first? The fuse in question is the "gauges" fuse. If it blows, a lot of things on the dash won't work.
This post is four years old. I suspect the problem is solved by now.
In fact, there is nothing on a vehicle that can destroy a generator from over-current as they are all self-regulating in that respect. You simply can't get more than what they're designed for.
What GM IS famous for is repeat failures of their generators. Since the new design was introduced in the '87 models, they went from the world's second best AC generator to by far the worst pile ever dumped on the buying public, and bbergquist has the proof. Because the voltage regulator switches on and off 400 times per second, the field winding acts exactly like an ignition coil primary winding and creates voltage spikes. Those spikes destroy the generator's internal diodes and voltage regulator. They can also radiate into adjacent wires and "induce" voltage spikes in them. When that happens to a sensor wire that computer can cause running problems when those spikes confuse it. Many running problems are identified as being caused by the generator by unplugging it while the engine is running. When the problem clears up, you know it's the generator.
The cure for those voltage spikes and the repeat generator failures is to replace the perfectly good battery at the same time. As they age, they lose their ability to dampen and absorb those spikes. That can be a problem already when it is just two years old. That old battery will work fine in '86 and older vehicles.
Monday, March 12th, 2012 AT 11:25 PM