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robertmorehead
12-24-2007, 03:25 PM
I'm at the stage of conversion of replacing radios and hooking up the rear speakers. I have been working on Pioneer systems currently, as it is a good value it believe.

What I have learned is the Radio is a "Can-Bus" system. It is more like a computer than a Radio. You will not find the normal Voltages of yesterday. The "VW" plugs are still the normal plugs to use, and will give access to speakers, ground, and Battery Power. Keyed Power must be supplied from another source. The Factory Harness has two "Can-Bus" Wires that do the talking to the radio and the van computer. There is risk of computer damage if improperly wired.

This Can-Bus system is present on many new vehicles, Ford, Chrysler, Chevy. But, they have "Can-Bus Adaptor" for them. the just plug in between the Van and The radio and correct the voltages and signals for an easy hook up.

What I want to know is:

-Are there any aftermarket "Can-Bus" Radios?

-Is there a Mercedes "Can-Bus" adaptor arround?

-Where Has been a goo place to Get "Switched Power"?

-Not sure on the Antenna Power connection? There is a pin on the harness for it. I will get this answer soon.

Man I didn't want to know this stuff!

-robert
www.moreheaddesignlab.com (http://www.moreheaddesignlab.com/)
custom vehicles
campers, van, trailers, RV, expeditor

merdas
12-24-2007, 03:45 PM
"Where Has been a goo place to Get "Switched Power"?"

I recently installed the Kenwood DNX navigation, DVD system and back up camera in place of "Sound 5"
I tapped into cigarette lighter just below the radio as switched power source. Hope that helps.
:cheers:

sikwan
12-24-2007, 04:15 PM
Robert, you don't need to use the CAN bus or even need a radio that is CAN bus ready. All the voltages and speaker hookups are there for any aftermarket radio.

The CAN bus is just for bidirectional communication between the items on the bus line or from a technician's electronic debugging tool.

robertmorehead
12-24-2007, 08:38 PM
Merdas:

I think the lighter has to be the plan. Does it stay active till the key is removed?

Sikwan:

The radio does Communicate with the Bus.

I can find no switched 12v power on the harness, like the 5cyl days (which I think you refer). If you know what pins to use on the 2007-08 please share. Unless you are thinking of combining the ACC and BAT leads and having a "Hot radio". That is not a professional installation. But, would keep from hacking in to other wires which is professional.

What I know is:

A1 = speed volume control
A2 = unused
A3 = Mute
A4 = Battery
A5 = Antenna ( should send signal from radio to Antenna Booster)
A6 = Bus +
A7 = Bus -
A8 = Ground

Voltage Key Out (important, radio stays on till key removed) radio unplugged at harness
A1 = speed volume control
A2 = unused
A3 = Mute
A4 = Battery 12.2
A5 = Antenna ( should send signal from radio to Antenna Booster)
A6 = Bus + 12.2v
A7 = Bus - 4v
A8 = Ground

Voltage Engine running radio unplugged at harness
A1 = speed volume control
A2 = unused
A3 = Mute
A4 = Battery 14.1 (alternator)
A5 = Antenna ( should send 12v? signal from radio to Antenna Booster with radio on, didn't think about testing this till now)
A6 = Bus + 4v
A7 = Bus - 4v
A8 = Ground


The BUS + actually looses voltage with the engine running. Man did that hurt my head!

sikwan
12-24-2007, 09:44 PM
The radio does Communicate with the Bus.

Robert, I never said that it didn't. I'm just saying that you don't need a deck that is CAN bus ready or even need to use the CAN bus. Plus, even if you had an aftermarket CAN bus ready deck, you still need the correct ID to avoid bus contention.


I can find no switched 12v power on the harness, like the 5cyl days (which I think you refer). If you know what pins to use on the 2007-08 please share. Unless you are thinking of combining the ACC and BAT leads and having a "Hot radio". That is not a professional installation. But, would keep from hacking in to other wires which is professional.

You're right that there's a reason for separating the ACC and BAT leads off the deck, but there's nothing wrong with tying it together if you do not want the deck to run off switched power. Nothing unprofessional about it (did I just write a double-negative?). You'd be surprised that a lot of people prefer it. :thumbup:

To answer your original question, I don't know of any aftermarket deck unit that utilizes the CAN bus or know of a CAN bus adapter.

Btw, my ACC is tied to switched power. :smilewink: