@Seanhump
@Sneaky Pete
@i860

 

The Stock antenna amp has connections for power, ground and signal - signal is switched 12v, fed by the audio system


circuit 30 is battery voltage positive - continuous
circuit 31 is battery voltage negative - continuous

 

Thanks. So if I understand correctly:
1 = 12 v radio switched
2 = not connected
3 = T31 battery negative, that is ground I presume
4 = T30 is battery 12v not swiched (continuous)

 

Yes.
The antenna amp consist of 2 circuits, 1 for radio signals and 1 for the signal from the remote key. The latter needs constant power otherwise you wouldn't be able to unlock/lock the car with the keyfob. The other circuit for the radiosignals is switched on/off with the signal from pin 1 from the AGW (blue/white wire). Like in the good old days was done for an electrically retractable antenna.
Power for the antenna amp comes from the rear SAM (FL) or from another circuit (pre-FL). I think, not 100 % sure...:wink:

 

Thanks guys, I guess I will dig up the connector under the pile of amplifiers and give it a try.

 

Interesting since I was messing about with my Dynavin HU (all HK gear removed). There is a switch for phantom antenna or not. I believe this is a power feed. Either way it seems to make no difference to the FM reception.

Maya via Tapatalk

 

That depends. One of the connectors on the HK amp is the control for the antenna amp. Did you make connections from the Dynavin to this connector?

 

In all honesty I cannot remember exactly. It's been about three years since I did the install. I know for sure the aerial is connected to the Dynavin and I recall something about Fakra? But that's about as good as my memory gets. I shall rediscover the Dynavin manual and refresh my knowledge.

Maya via Tapatalk

 

Hi, does someone know the color or the antenna amp power switch wire under the dash that needs to be connected to the switched head unit wiring?

 

Hi @maxter, welcome to SLKWorld.com: The #1 Mercedes-Benz SLK Forum from Canada!

Your first post should be here Introduce yourself to the Forum Membership

First please update your location and vehicle (Put Looking!)(year?: 1996-2018, model?: 32, 43, 200, 230, 250, 280, 300, 320, 350, 55) in your profile as it helps the members answer your questions which usually are based on that information if you haven’t. This takes about 30 seconds to do.

Follow exactly to update: ‘Usercp’ at the top of page, then ‘edit your details’ on the left side, ‘additional information’ near the bottom, edit your ‘location’ and ‘vehicle’. Info in your garage does not update your profile.

On a smartphone: https://www.slkworld.com/new-member...troduce-yourself-here/330737-how-update-your-profile-post-intro-smartphone.html


Thank you

 

Open Question

This thread is labeled RESOLVED, but I don’t see a response to maxter’s question about the location and colors of the wire under the dash that provides power to the radio antenna amplifier. I could not locate mine either, so any information would be appreciated.

In the interim, here’s my solution to an unpowered antenna amplifier. Warning, - it may not be for everyone.

When I purchased my 2006 SLK350 it had an aftermarket head unit (Kenwood DNX691) that was installed by the previous owner. The radio reception was really poor. I looked at the antenna amplifier and found that the power connector was different from the drawing in the first post in this thread but with the same basic wiring. On my car’s connector there are just three pins, - green is ground, blue/red is continuous power for the key fob antenna amplifier and blue/white powers the radio antenna amplifier. With the radio turned “on” there should be power to the blue/white line. In my case, there was no power. I pulled the radio out of the dash and found that the Kenwood head unit’s antenna power line was, in fact, connected. But it was connected to a blue wire that disappeared into a snarl of wire under the dash. Whoever did the installation had cut off the OEM connectors and, in the process of hooking everything up, had connected the antenna power output to the wrong wire. (Or maybe that blue wire goes to a power amp? I do have the Harmon Kardon audio option.) In any event, there was no blue/white wire to be found.

So I took a direct approach and jumpered the antenna amplifier’s red/blue wire to the blue/white wire at the antenna amplifier plug (see photo). This means that the radio antenna amplifier is powered continuously.

This may not be a good option for everyone! I checked the current draw as part of connecting the jumper, and the radio antenna amplifier draws 70 ma. I believe that the normal “everything off” current draw for the vehicle is also about 70 ma. So powering both amplifiers continuously probably doubles the “everything off” current draw. This is acceptable to me because I connect a battery tender whenever the car is in the garage. But it could be an issue if you make this modification and the car sits for more than a week or so without a tender connected.

Again, if anyone knows how to locate the antenna amp power wire under the dash, please respond. Making the proper connection there would be a much neater solution. Also note that information about OEM head unit connector pins is not useful to me because my OEM connectors are long gone

 

Well looking at the colors on the connectors compared to the story of Bill then I would asume that the black wire is the Blue/White from Bill’s car and that is the Switched 12v for the radio antenna. White would be earth. So connect 12v to the black and fuse it at 1 amp to be safe. Then try radio reception. Good luck.

 

Hi
Good day
Thank you for your reply.

Will it later by applying a 12 volt to the black wire via a fuse.
Hope it works but a lot of works because have to disconnect my windscreen antenna

meaning have to remove the HU set to access to the back of the HU set.

Thank you & have a nice day

 

I agree with Merc55. Use caution here! Some experimenting is in order, but a fuse is essential. My post above is for my car, a 2005 US SLK350 whereas Hui has a Japanese 2008 SLK200. Assuming that he has the correct connector, the wire colors are clearly different. Maybe a member with RHD and in the far East or OZ can check their vehicle and provide some insight.

 

Hi
Good day
Thank you for your reply.

Will do it later by applying a 12 volt to the black wire via a fuse.
Hope it works but a lot of works because have to disconnect my windscreen antenna

meaning have to remove the HU set to access to the back of the HU set.

And of course I have the right connector since I unplugged from the amplifier.
But I will NOT actually apply a 12volt dc directly to the black wire even with a fuse.

What should be normally be done on the safe side is to:
cut the black wire, then apply the 12 volt to it.
If it doesn't work, then have to join the black wire back with soldering.
Then repeat the same with the white wire.

Surely one of the wire must be for the FM antenna amplifier? right?

Merc have the habit of having two wires for a device
that are both in either negative or positive when you test it
but it will change one of the wire to negative or positive
when the device is switch ON,
it done with a two way relay or switch.
(eg: power window motor)

Thank you & have a nice day