1.5 hours enough to transit through HAM?
 

I'm flying UA from EWR-HAM then LH to MUC (same ticket). Only have 1.5 hours in Hamburg. I assume I don't have to get luggage. Will I have enough time to get through custom? Do I need to go to a different terminal?

Yes, that is plenty, otherwise they wouldn't have sold you that connection. You won't see your bags until you get to Munich, so that's also where you'll be going through customs, not Hamburg. You will go through immigration in Hamburg, but 90 minutes will be more than enough. I'm pretty sure you will arrive and depart from Terminal 2, but in any case both terminals are connected airside. HAM is a lot more compact than EWR.

Terminals are connected airside and landside. You could make such a connection in under 30 minutes easily.

HAM is nothing like MUC or FRA, or even DUS. It's pretty small actually.