progressive industries ems-pt30x E3 error code

1st, I am assuming you have a voltage read out on the unit. My internal Progressive does. If so, what are the voltages. If you don't check the post with a VOM. There should be some indication of error codes in your manual. If the unit it internal to the coach, like mine you can adjust the pots inside if they are reading the voltage incorrectly. Check with Progressive before you do this, as I am not with my coach now and don't remember which pot is which. If this is necessary and you have a read out be sure you synchronize the voltage of the LED with that of the incoming voltage to your coach at your fuse box.