DME Relay Pinout
Here are the pinouts from the 84-89 Carreras and the 944s/964s/993s (which I think are all the same).
Pin 85 [1] - Ground to the DME/injector relay coil
Pin 30 [2] - +12V directly from the battery
Pin 86 [3] - Switched +12V from ignition switch (bus 15)
Pin 87b [4] - +12V to the fuel pump, switched by the fuel pump relay
Pin 87 [8] - +12V to the DME and fuel injectors, switched by the DME/injector relay
Pin 85b [9] - 0V switched to the coil of the fuel pump relay from the DME, pin 20
Note that Porsche/Bosch changed the pin numbers of the relays in the documentation. In the older docs like I have for my 85, they're labeled with the 85/30/86 numbers. In later docs (and on the newer relays) they have the 1, 2, 3 numbers.