Is it possible to check on board charger.Its a 3 bank and on one of the banks the full charge light never comes on took battery to have checked they said it was ok.
I checked mine the other day after chargin em with the onboard charger by hooking up an external digital charger to see if all the batteries were at 100%, and they were. Might try that. You may just have a blown bulb, or could possibly have one bank not working properly