Merc Monitor Issue

Having some trouble installing a Merc Monitor gauge (V7), was hoping someone from the 2cool brain trust may could offer some advice. When I turn ignition on, it doesn't do anything - like it's not getting power. Owners manual says I should see a splash screen when powered up. The majority of it is plug and play - one harness ("external power") had two wires, I tied to switched 12v and ground buss. The air temp sensor/harness is hooked up. Not running any additional "system" gauges or anything on the NMEA (yet). Blue cable runs from motor to an adapter harness and then to the gauge. I have some $$$ invested in this, so am kind of bummed out I cant get it to work. It seemed pretty straightforward. Motor still starts and runs fine - 2007 ProXs 250. I just sent an email to the place I ordered all the parts from - Will follow up with a call in the morning. Thought I'd also see if any 2coolers were in the known on these gauges while I was at it. Thanks!