I had mine fail this past weekend but when it failed it resulted in NO power to the car at all. If it is failing because it is draining the battery while racing then that seems different. Maybe at some point it was hooked up wrong creating a possible surge to the alternator which has affected the resistor and or polarity of the alternator. I am not an electrical genius but this is kind of how it was explained to me when I did mine wrong years ago. When the car was running the alternator actually drew voltage from the battery instead of charging the battery. This resulted from turning off the kill switch while it was running creating what was explained as a "surge" that affected the resistor. (My alternator has a resistor built into it not separate as some other cars.) Not sure if this helps or not... could be just a bunch of BS that I got so I would purchase a new alternator. FYI that same kill switch with the new alternator and wired correctly has lasted for about 5 years on the outside of the car, through winters in the NE with the car stored outside until about 2 years ago. only issue I have is if I turn off the car and leave the kill switch on for 20 min it kills the battery and will not restart without a jump start. Never figured that out to this day!

Stephen