That's the Control Pressure Regulator, also called the Warm Up Regulator (WUR) in Bosch books. The main system fuel pressure is controlled inside the Fuel Distributor.

Those Regulator wires are just for a heating element that speeds the transition from cold/rich mixture to warmed up/leaner mixture. The car will run without it. Just takes a bit longer to lean out.

The black wire should be grounded, as you'd expect. If you are probing the Blue wire with the connector off, there are two parallel paths back to ground—thru the Aux Air Valve heater and the Lambda Relay coil. Those 2 items would need to be disconnected to isolate the Blue wire.

But all that aside, there is no 12V there with ignition on. That won't happen until the FI relay (aka Fuel Pump relay) gets picked during start & running. The 12V you're looking for comes from FI relay terminal 87b.

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Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.