Since you are not getting a green light on the remote switch, the inverter is not coming on. Lots of things could be wrong from simple stuff to more complicated stuff. I guess if you call your light switch a "light off" switch, it needs to be off for the light to be on. The battery disconnect switch...disconnects the batteries, it's better to say the batteries are on or off, rather than the disconnect is on! (couldn't help myself, sorry) First, find the inverter and turn it on directly on it panel. If that turns it on, check the low voltage "phone wire" that runs from the inverter itself to the remote on/off switch. It it doesn't, put a volt meter across the heavy gauge cables on the back and see if it reads 12 volts or so, if it doesn't, chase it down and see why it isn't connecting to the batteries. If there is 12V, and the inverter won't go on from the panel, there is a fault in the inverter. A lot depends on the inverter itself, on my Xantrex, there is a 100 amp fuse OUTSIDE the inverter where the positive wire connects. Find your fuse and check it out.