Most of us test only the PC on the bench, and have the headunit in the vehicle.
Probably, but I can't say for certain based on the information you've given.Will it work fine in my car when I install it this coming weekend? At that time, the head unit/screen will have different power sources from the car. Or should I put off the installation for a while? Any input is appreciated.
I suggest installing the headunit in your ride first, then bench test only the PC portion of it. If the PC works, then configure it the way you want and move it into the vehicle.