Bought a Multplus 12|500|20 for my Campervan install. Finally got it all hooked up neatly tucked away (with enough ventilation) under the drivers seat, and ready for first switch on... switch it to ' on' and after a couple of clicks and flashing LED's: nothing. After disconnect and reconnecting, still nothing, swithcing to charge just gives a solid alarm led. Is the unit DOA? The troubleshooting table in the manual does nog give a solution. Any tips?