The first thing that needs to be done is an autopsy on a failed alternator to see what part of it failed so we can have an idea of where to start looking. The next thing that you must be aware of is all alternators are physically incapable of producing more current than they were designed for. The only way one can overheat is if it is being forced to generate its maximum current for a long time, as in many minutes. That can be determined with a standard charging system test. You can do the first part of the test yourself with an inexpensive digital voltmeter. Measure the battery voltage with the engine running. It must be between 13.75 and 14.75 volts. If it is considerably higher than that, it is being run wide open by the voltage regulator in the Engine Computer. That can be verified by measuring the voltages on the two smaller wires plugged into the back of the alternator. If we get that far, I will have to dig up a wiring diagram because the circuit changed in the early 2000's from what I had memorized.
Jul 23, 2016 at 8:59 PM
