checking 380sl fuel pump relay socket connections
 

The car would die intermittently from the FP relay cutting out - moving the relay harness made it repeatable - traced it to the +12v battery voltage dropping out (socket pin 8 on 7-pin relay).

Pulled the connector apart by prying 4 retainer tabs on the socket side to remove the shell - this came off easily by holding the shell with two fingers and pushing socket with thumb while prying tabs one at a time. Then pryed up two tabs (one at each end) from side of socket to release the connectors/wires.

Solder connections were good, but the socket had to be squeezed a bit tighter (to close gap). No more cutting out when flexing the harness.

FPRs are prone to failure but it could be one of the input/output signals, supply voltage, or ground. I made a small wire that made it easy to test the relay in circuit (which I should have made a longer so there's no chance a test clip will touch the back of the PC board when the FPR cover is off).