Hi,
I am currently (and slowly) replacing the Head Unit in my 2005 SL350 with an Alpine X800D-U, which will be connected to a JL HD900/5 Amplifier through to the original M-B Speakers. I have received some very good advice so far from other sources, but would appreciate a little more detail in places to clarify whether my intentions (regarding connections) are the most appropriate. I know that more than one of you will have completed similar installations in the past and would appreciate your advice ... so here goes:

I have measured all of the speaker impedances and am aware of how M-B have connected them together, ie, 8 speakers where the rears are paired in parallel (2 Ohm each); 2x door speakers each (2 Ohm each); Centre Speaker (3.5 Ohm) and Sub-Woofer (0.8 Ohm). As the JL Amp is 5-Channel, it has been suggested that I connect as follows:
1. Sub-Woofer to Sub-Woofer (however, concerned that the JL Amp might not be happy powering an 0.8 Ohm speaker) ... any suggestions?
2. Front Channels connect to L/R Front M-B Low- Mid Range Speakers.
3. Rear Channels connect (in series) to L/R Front M-B Mid-High Speakers and Rear M-B Speakers (separated obviously).
Does this sound reasonable? In addition, as the Centre Speaker is not used in this arrangement, any issue with connecting this speaker directly to the head unit using one of the non-amplified output channels?
Then, what about connecting the Alpine Unit to the Steering Wheel controls? Is there a specific adaptor lead that I can 'just' plug in and would this also allow the clock to be adjusted?
I am in the middle of mounting the Alpine Unit in the dash (no issues with the Amplifier - same place as the BOSE Amp (removed)). Manufacturing the dash trim around the Alpine is coming on, but I'm in my 3rd iteration ... caused because I did not wish to disturb the OEM setup until the last moment, consequently, had to rethink my plan after I saw how the original unit was mounted.
Anyway, great to receive some thoughts on speaker connections, do I need to replace the sub-woofer and a recommendation for a steering wheel adaptor cable that works.
Regards and looking forward to completing my project over XMAS.

Wolfie Souter
2005 SL350
Westbury, Wilts, UK

 

You know Alpine make the 8000U as a Mercedes perfect fit head unit for the Vito and ML, and they also do a direct replacement amp too.

I would look at that amp, that steering wheel control kit etc., you may find it saves a lot of grief?

http://www.alpine.co.uk/p/Products/alpine-style4808

 

Thanks for this advice gIzzE. Although the Amp plus speakers are a specific fit to the ML, I have asked Alpine whether their Canbus Adapter would work in the SL. I will update this post when I receive their response.

 

A very quick response received from Alpine ... the Canbus Adapter will not fit an SL - adaptors are programmed specifically to the vehicle. They suggested that I try Connect2 or InCarTEc, however, I had already spoken to both companies where their adapters do not fit a 'facelift' (widescreen) audio system with MOST link.