only occasionally does the alternator charge. generally when first started it will charge only in the 12 volt range and after a short run time it will drop to 9V and the check gauges light comes on. I've had the alternator and battery tested and they are good. I've replaced the ECM and no difference. I've cleaned all of the engine grounds that I can find. I'm looking for another direction to go as I'm at the end on my rope.