fuel pump relay bypass?
 

380SE fuel pump gets no power. I suspect relay. Is there a serious problem that will develop if I run a wire straight to the fule pump from the battery to get the car to run? What does the relay do besides function as an on/off swithc?

The other functions vary, but none keep you from doing the testing you desire. The most common other function is trans kickdown control and rpm limiter.

The easiest way to do what you desire is to pull the relay, construct a jumper with a fuse inline and jump the relay socket between term 30 and term 87.