Mercedes-Benz Forum banner

1 - 20 of 28 Posts

·
Registered
2001 SLK320, 2001 C320
Joined
·
2,267 Posts
Discussion Starter · #1 · (Edited)
It was time for me to do something about the stereo in my 2001 SLK320. The factory Becker gave me uneven FM reception at best, and to my ear it sounded just plain lousy. Most stores won't even touch these cars, but doing a DIY head swap is actually pretty easy. I don't describe the whole process here, but I do include all the pieces of the puzzle by giving helpful links.

I went to the Crutchfield website (you can guess the url) and picked out an Alpine CDE-9845 for only $159. It's last year's model, so it's on sale. This unit had everything I needed: auxiliary input jack on the back, a pair of line-outs, and the ability to turn off the PA amp when using line-outs. It also comes with FREE connecting adapters for both the wiring and antenna! Radio removal tools are also in the package. Free shipping, too...



Here's the trick: According to Crutchfield's website, there is no data available for the 2001 SLK. So I lied and said it was a 1998 Mercedes C-Class without Bose. This little ruse got me the right wiring harness connector and antenna adapter.

Next, I downloaded the excellent instructions from slk32.com (http://www.slk32.com/pages/radioupgrade/slkradioinstall.html). These instructions describe the process in great detail.

However, there are a few changes to this procedure that I'd like to note. For starters, I did not need to cut the wiring adapter in half -- it fit perfectly. About the only difference I noticed between the chart for the wiring adapter and actual wiring of the head unit is that the 12V (always on) and 12V (switched) lines are reversed. Crutchfield also makes note of this when you buy the head unit. Everything else seemed to match. I'd suggest checking the wiring yourself anyway.

Here's a link showing the stock head unit wiring: http://www.beckerautosound.com/1492.html

Also, I used the LINE OUTS and not the speaker outputs -- these feed into the Bose amp, which I kept (for now). I also soldered all connections and used shrink wrap (hey, I'm an electronics geek).

Once everything was wired up, I noticed that I was getting sharp pops every time I changed stations or settings. From a previous thread, I learned that a "ground loop isolator" from Radio Shack (part no. 270-054) installed in the LINE OUT wires got rid of the problem. Easy fix.



In order to stuff all the spaghetti at the rear of the radio into the area behind the dash, I removed the kick panel next to the console on the passenger side. To do this, I unscrewed 2 screws that hold the panel under the glove compartment and pulled out that panel. Then I unscrewed the plastic screw holding the footwell vent, pulled out the vent, and removed the screw holding the panel in place. It takes a little creative tugging to get the panel out, but it can be done. Then I could easily see into the area behind the head unit.

Finally, I used some foam rubber to help keep all the bits from rattling around back there. You could also use tie wraps to hold stuff down, but this method could be a little awkward.

How does it sound? Fantastic!!! The whole thing took me a couple of hours, and it was really worth it...
 

·
Registered
SLK 230 (now gone), SLK 350 Facelift
Joined
·
78 Posts
Interesting comment on the 12V feeds being switched - I have a Sony CDX 770 (or similar number!) fitted from new by dealer (option in UK) and it only works with the ignition on - dealer may not have been aware if they used a similar adaptor. Must get brave and pull a few bits out to see one sunny day - if we get any this summer!!!

Did you note the wire colours for the 12V feeds - to save me getting the meter out as much as anything.
 

·
Registered
2001 SLK320, 2001 C320
Joined
·
2,267 Posts
Discussion Starter · #4 ·
robint said:
Did you note the wire colours for the 12V feeds - to save me getting the meter out as much as anything.
I think the dealer did this right. Normally, the radios only work in these cars with the ignition on. Unlike my '72 Beetle, where the radio would work at any time...
 

·
Registered
1999 SLK 230
Joined
·
937 Posts
Bazzle said:
The 12v always on is to keep the station and security code in memory not to run radio when ign off.

Bazzle
With the ignition off, push the radio on (volume) button and report what happens.
 

·
Registered
1999 SLK 230
Joined
·
937 Posts
page62, I'm glad that you're happy with the sound, but the Radio Shack ground loop isolator is not the best from a fidelity standpoint. High-quality (wide bandwidth) isolators are pricey, $100 or more. Inexpensive ones typically roll off the bass frequencies considerably.
 

·
Registered
2001 SLK320, 2001 C320
Joined
·
2,267 Posts
Discussion Starter · #7 ·
DickB said:
page62, I'm glad that you're happy with the sound, but the Radio Shack ground loop isolator is not the best from a fidelity standpoint. High-quality (wide bandwidth) isolators are pricey, $100 or more. Inexpensive ones typically roll off the bass frequencies considerably.
It still sounds better than the Becker...and it's only a short-term solution. The Bose amp is going to go "bye-bye" one of these days...
 

·
Registered
2008 CLK550 CAB
Joined
·
94 Posts
Nice install! I too soldered my connections and used shrink wrap. Not only better but after a few hot summers, electrical tape can become gooey.

Agree with the swapped CONSTANT ON and SWITCHED 12v.
 

·
Registered
SLK 230 (now gone), SLK 350 Facelift
Joined
·
78 Posts
Nothing happens on trying to switch Sony unit on but it clearly has a 12V feed somewhere to hold the memory stuff. Supposed to have an ISO connector, but manual tucked away in car, its dark and wet and I'm going to Cardiff all day tomorrow to watch the Heineken Cup Final (proper sport with an oval ball......) so it will be Sunday before I get round to it! Have a nice Saturday.
 

·
Registered
1999 SLK 230
Joined
·
937 Posts
On my US system, I can push the radio on (volume) button to turn the radio on without having the key in the ignition. It shuts itself off after a while. So, the point I was trying to make (and be a bit of a smart*ss at the same time) was that the +12 constant lead is used to power the radio, not just to keep the memory alive.
 

·
Registered
1999 SLK230 Kompressor
Joined
·
332 Posts
DickB, I also did the conversion and installed an Alpine CDA-9847. That feature only seems to work with the OEM headunit OR with a unit that has the capability to run off of the 12V power. My Alpine manual specifically states that the unit will not work with the ignition switched off. So, perhaps that is the case with all Alpines...dunno.
 

·
Registered
2001 SLK320 Sport
Joined
·
93 Posts
well im getting annoyed trying to install my headunit... Ive tried quite a few things now. I cant get any sound. Radio turns on fine all lights work seems like antenna works. but no sound. Is there a factory amp that powers the front and rear speakers? That may be my problem? Ive got the wires to all 4 speakers wired. the grounds. I have a factory 6cd changer is that the problem I didnt wire anything to that connector ill take pictures to show what I mean if you dont understand. but whats the problem im having??
 

·
Registered
2001 SLK320 Sport
Joined
·
93 Posts
hmm ive researched it, ive read that page 5 times now and it says nothing about how to power the amp to run the speakers or whatever. Thats why I posted.....
 

·
Registered
2001 SLK320 Sport
Joined
·
93 Posts
Wow I missed that thanks for the help it worked.

just wrote all the wires down from the Mercedes harness to the VW harness to the headunit harness. Figured out which wires matched up with what on the VW and then figured it all out that way. Thanks for the help it works great...:thumbsup:
 

·
Registered
2000 Mercedes S500.2001 Mercedes C320 Sport
Joined
·
5 Posts
Hey i didnt see on here where you posted the colors of the wiring. I want to splice into the 12v but im not sure which wire is which. I have heard that it can be splice into the lighter but since my radio is already out I'd like to hardwire into that
 
1 - 20 of 28 Posts
Top