Any way to test the units outside the bike?

 

No. It's controlled by the CAN bus. I don't think you could even power it up if it's not connected to the bus. What's the problem you're trying to solve?

 

no problem, buying a unit and wanted to see if I can get power to it to make sure it fires up

 

Best way would be to have the seller plug it into their bike to show you it works, beforehand.