MB69

My son installed an after-market head unit in my 1989 300E. It seems that when he put the wires where they should be (I didnt do it so I assume he put connected them correctly...he used diagrams he found on-line) the unit would only power up when the headlights were turned on...?

Everything else worked. Any ideas what he did wrong?

Thanks in advance.

Saijin_Naib

Sounds like he tapped either voltage or ground into a wire harness that was on only when headlights are on, such as interior cluster light circuit. It is generally wiser to hook to the ignition circuit.

However, the stock radio can be used without ignition and is on a timed circuit to turn it off after I believe 2 hours. Whatever circuit that is is by far the best place to put it. Zee Germans had it fairly well sorted from the factory in that regard :P

Floobydust

I think someone has mis-wired the "illumination" feed (orange wire) and the "switched +12 vdc" feed (red wire) to the new head unit. I'll bet the the background illumination in the head unit comes on as soon as you start the car. Locate the red and orange wires coming out of the new head unit and swap the wires they are connected to. Things should work after that.

- FD

watut

Does anyone have a wiring diagram for a 95 E320 cabrio without a fader