That sounds like the same issue I'm having. Different monitor, but same power supply, m2-atx. Monitor powered directly from the car.
The keyboard also doesn't appear to power on. It will blink, then go off.
My theory is that it has to do with the Cold weather. If you're in NY then your weather is the same as mine.
What I've been doing is letting the car warm up (with the heat on, not just the engine). After doing so I'll reset the pc power and everything will boot up fine. Electronics don't seem to work well in freezing temperature. When it was hot outside it worked fine.
I'd like to know if that works for you?