Last October the engine and battery light on my 05 FXDI would come on after bringing up the rpms as soon as I was the road. After making sure the battery was fine, I replaced the regulator. Problem solved. For about a few hundred miles and a few weeks anyways. I put the bike away for winter until now. I've since replaced the battery and negative cable. Using a multimeter I checked the battery yesterday with the engine off and running with the rpms cranked. The meter showed about 11.7 volts with no change when revving the engine when the warning lights would come on. I'm going to replace the positive cable since I've already bought it anyway. My question is how do I test the regulator? Pictures would help greatly! Also what might be causing these regulators to cease functioning?

 

I would test the stator with the regulator pin removed at the crankcase. More than likely that is the problem that your regulator went and took out the stator because they are both fragile. I've gone through three sets on my rigid for different reasons. the way to test it is to remove the regulator connector that plugs into the front of the crankcase and put the ampmeter into the two holes. Check with your manual for what it should read output wise.

 

The way to test your regulator is to get a multi-meter, unplug the cable going into your regulator from the stator. It will have 3 pins connect the ground, on the battery to the multimeter and then individually connect the other end to the pins on the regulator, there should not be any current. If there is then the regulator is toast. Chances are if your regulator is gone then it is due to the stator. Don't ask me how I know... I did exactly as you did hoping it wasn't the stator, had numerous suggestions on what was the problem... replace the stator, if your regulator is gone, you will have to replace the regulator as well. You may want to check the engine codes (if in fact you are having issues you will find that the codes identify an overcharge situation).