On my 92 R52, I have a low voltage problem, or should I say still have. I have cleaned grounds, replace the main cab relay, had the alternator checked, put a bigger main breaker on. One of the things that happens is the longer your run, the lower the volts go. One of the things I wonder about is the resistor in the console for the alternator. What does it do? why do you need it? On other GM alternator equipped things, you don't have a resistor, what special thing is this one doing. Or is it to do with the hotter engine compartment? Is it possible for the regulator to slow down. Looking for suggestions. This combine sure has its share of electrical issues.