W126 300SEL becker radio

[bruiserbruce]

I intend to replace the radio with a cd tuner.I removed my becker 738 grand prix radio and did not see an automatic aerial connection on the back. When I replaced the same radio, and reconnected the plugs I removed, the radio worked, but the aerial failed to go up when the unit was turned on. My W126 wiring diagram shows a blue wire going from radio(A2) to a dual relay (S69). Does anyone know where S69 is situated? Is it in the antenna body? How is S69 triggered from the radio without a blue wire? With all the light in the world, I cannot see the blue wire connecting to the radio. Confused!

 

[bruiserbruce]

There is a black covered wire that has an uncovered flat terminal, and that looks the perfect candidate for an earth, and that fits the chassis terminals in the center of the back of the radio. As it happens, this wire also fits the 'twin terminal' next to the power terminal block, and which gets 12V when the radio is turned on. If you cut open the black sheath of the wire, lo and behold, it is 'blue', and the only earth connection to the radio is the brown wire in the power terminal block.