My 94 e320 Wgn has a Becker 1692 with set up for car phone. Connector to antenna feed has A] Brown, B] Black, C] Red/White and D] Blue. A, C & D come from one harness while B comes from another. From reading other posts, I assume A is ground, C is always hot and D is the "trigger."

Voltmeter & continunity test shows A ground is ok and C is 12.+ volts.

I'm attempting to install a replacement antenna with Red for power, White for trigger and Black for ground. With the antenna grounded and its Red <=> Red/White, the only way I can get the antenna to do up/down is touch the antenna's White to the MB's Red/White. Blue "Trigger wire(s) have no effect. I couldn't get any readings from the blue wires.

Attached photo shows plug and wires as they would wire into original MB antenna's circuit board. Brown to Brown, Black to Blue, Red/White to White and Blue to Blue 2x (cut wire is power feed to MB's antenna splitter) All pins go straight through the connector.

What't the purpose of the B] Black?

How does the D] Blue "trigger" function? How can it be tested?

Thanks
Bob

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