Installing a Panasonic CX-DP801 CD Changer  in our ML320.

Locating aCD Changer with a converter for  the Mercedes proprietary changer interface cable was the key to this part of the upgrade project. Fortunately AUTOTOYS.COM put together just such a package. (note: their web page incorrectly describes the means of accessing a disc in slot 7 or 8; it is press 1 then 6 or 2 then 6).

Also it turns out that you can just order the head unit to CD changer cable from Mercedes (part no. 163-540-31-05). This cable was then run from the head unit down under the console, under the carpet to the changer under the driver's seat. That cable is designed to reach from the dash to the back of the vehicle so it is a "little" long. But given that 2 pairs of shielded wires are in the cable I did not attempt to shorten it, the extra was just coiled up and hidden behind the head unit.

Mounting the CD Changer under the driver's seat

The location chosen by Mercedes for the CD changer, way back in the cargo area behind a panel, never appealed to us. Both because access to this area is inconvenient (to impossible when the truck is fully loaded) and because this area above the emergency jack seemed better suited to other emergency supplies. So when AUTOTOYS.COM made an alternative available I started looking for other locations to mount the changer. The Panasonic CX-DP801 while very small for a 8 disc changer, was too big for the glove compartment or the storage bin in the console. That left under a seat, with the space under the front passenger seat already taken by a storage drawer, leaving under the driver's seat as the best location.

Mounting the changer under the driver's seat involved these steps (detailed below):

  1. Trial fitting the changer to verify that it would fit and what the best position for it is.
  2. Remove the head unit from the dash, detach the OEM changer cable.
  3. Remove the driver's seat from the vehicle.
  4. Remove the console from the vehicle
  5. Remove the door sill (front and rear driver's side doors)
  6. Lift carpet, verify that no important wires or components are in the way.
  7. Modify base brackets to fit floor pan contour, also modify side brackets to mate with base brackets.
  8. Route cable from the head unit through the console under carpet to the desired position.
  9. Replace / reposition carpet cutting holes for base bracket bolts.
  10. Mount changer cable protocol converter between base bracket bolts.
  11. Attach side brackets to changer and secure side brackets to base brackets.
  12. Replace door sill, console, head unit, and driver's seat.

Trial Fit

These 2 (floor mat level) images show the trial placement of the CD Changer.

The first picture gives an idea of how the changer will (does) look when you squat down and look in from the open driver's door. The second picture shows how the (already bent) side brackets will fit and that there will be (is) space under the changer for the converter.

The 2 brackets that attach to the sides of the changer are reversed (from their orientation described in the Panasonic installation instructions) for increased clearance, also they must be bent to match the slope of the floor where the changer will be mounted. The base brackets that attach (with double stick tape) to the floor (under the carpet) and provide the anchors for the side brackets to bolt to, must also be bent to conform to the shape of the "ridge" in the floor. (see below)

Head Unit Removal

The M-Class head unit (radio) can be removed, it just slides straight out, after 2 spring loaded catches are released. Simple enough if you have the right tool, but I managed with some other thin strips of metal (not recommended). As you pull the head unit out you must be careful of the antenna connector (on the right hand side of the head unit), remove it from the head unit when you gain access.

This picture shows the back of the head unit, with the CD changer cable connection on top.

The left side (facing the front of the vehicle) of the head unit is the location of the CD changer cable connection, also the power and speaker connections. The CD changer cable is the top, 10 conductor, connector. If you remove all the other connectors the head unit can be removed from the dash, easiest for later steps but have your radio code handy!

Driver's Seat Removal

The M-Class driver's seat needs to be removed to gain access to the area under it, obviously. The first thing to do is disconnect the electrical cable, which can be found under the back of the seat. You can remove the 4 screws holding the plastic under seat trim to the seat frame (note: you could skip this step but be careful not to rest the seat on this trim). This trim can't be completely removed until the left rear seat bolt and cargo tie down D-ring are removed. Now the 4 seat bolts (see the uncarpetted locations in the picture below) need to be removed, using a Torx E14 socket (note you will need to treat these bolts with a thread locking compound upon reinstallation).  The seat can be lifted out and set beside the truck, so that the seat belt can stay attached.

This picture shows the area under the driver's seat, after it was removed (the yellow screw driver is inserted into the existing opening in the carpet where the changer cable will emerge). More or less in the center of the picture running top to bottom is the ridge where the CD changer will be (is) mounted.

Console Removal  

The  M-Class console needs to be removed to permit the routing of the new CD changer cable. This is possibly the most complicated part of the job.

  1. Set the emergency / parking brake!
  2. Remove 2 Philips head screws in the bottom of the console storage bin (a long screw driver makes this much easier). Console storage bin removed, 2 console  retaining screws, rear cupholders and  sound deadening mat visible
  3. Remove the storage bin, remove the philips head screws at the top rear of  opening for the storage bin that secure the storage bin lid.
  4. Remove the trim around the transmission gear selector (be careful  not to scratch the console trim, faux carbon fiber or wood).
  5. Gently pry open the 4 retaining clips on the rear window controls at the rear of the console (note: how the cable leading to these switches is retained by a special hook molded into the inside of the console, just visible in the lower right of the picture above).
  6. Gently push the console trim from underneath (reach in through the storage bin opening), there are 2 pressure clips near the storage bin opening and 2 more near the gear selector.
  7. Remove the wiring harness from the lighter, note a small light bulb stays attached to the harness.
  8. Note the position and type of the 4 connectors from the wiring harness to the window and mirror control mounted on the console trim piece (I put labels on the trim pieces and the wiring harness connectors). Remove the 4 connectors from the console trim piece (I found it useful to wrap some tape around all the harness leads in this area so that they were easier to keep together).
  9. Remove the console trim piece.
  10. Remove the 4 philips head screws holding the console in place, 2 under the storage bin (see above) and 2 under the console trim.
  11. Now insert the key and shift the gear selector out of park (you may have been wondering why I didn't recommend disconnecting the battery at the start). This provides the clearance needed to lift the console up and back to remove it.
  12. Remove the foam sound deadening pad from the top of the transmission / drive line tunnel.

This picture shows the console removed (harness from step 8 is in the center)

Door Sill Removal

The door sill trim needs to be removed so that the carpet can be lifted up to provide access for mounting the CD changer base brackets on the M-Class floor pan. This is relatively easy, but you must pry some plastic parts apart so work slowly and gently. The center sections (the parts with the little ridges) of the door sills can be pried up to expose several philips head screws, remove them. Near the bottom of the B-pillar (vertical part of the door frame) are 2 round plastic plugs. You need to carefully pry theses out to expose the last 2 philips head screws holding the door sill in (note it is still attached at the back of the rear door but you can now lift the carpet under the driver's seat so it's not a problem). (see above in driver's seat removal picture)

Modifying Base Bracket

The Panasonic CX-DP801 CD changer comes with some very nice mounting brackets, two 5mm bolts pressed into a heavy piece of sheet metal. These brackets mount to any flat (metal) surface with double stick tape. Only I choose to mount the changer where there was not a nice flat metal surface, on the floor pan ridge that runs across under the front of the driver's seat (you could just mount the changer under the back part of the seat).

This picture show the area under the carpet under the driver's seat (unbent bracket placed near its final location).

This necessitated cutting and bending the brackets to conform to the floor pan (using a hacksaw, a vice and a big adjustable wrench). Once the brackets were modified, I affixed one with the double stick tape. The the side brackets were attached (reversed from the orientation called for in the directions) to judge how much they needed to be bent to conform to the shape of the floor pan and fasten to the already positioned base bracket.

These pictures show how (much) the base bracket nearest the door needed to be modified to fit the floor pan, compared to the inside base bracket shown in the last picture.

The side brackets were removed and bent (You need to realize that these "and bent" operations requires some number of tries). The changer with the bent side brackets attached is then used to position the second (inside) base bracket, which is modified a little and attached with double stick tape. Holes are made for the base bracket bolts in the carpet and it is pushed down over them and back into position.

Routing Changer Cable

If you already finished mounting the changer this step will be a little harder (guess how I know that?). Start by feeding the new Mercedes CD changer cable into the head unit opening in the dash (or you can reverse this whole sequence). Feed the cable out from under the dash in the center console, run it along the side of the other wiring bundles to near the rear of the console area. Now feed / pull it under the carpet near the rear of where the driver's seat mounts to a precut ("+" shaped) opening in the carpet under the seat. Feed enough cable to connect to the converter, then coil or some how secure the extra in the dash behind the head unit opening. Connect the cable to the head unit, reconnect the other head unit cables, enter the radio code, insert a CD cartridge (with CD's in it of course)  and test that the head unit recognises the changer and will play discs (I can offer not suggestions if it doesn't, because mine worked the first time). Insure that you prevent any rubbing of the cable on metal brackets either by rerouting or installing some protection (I used thick adhesive back rubber padding).

Final Changer Mounting

Ok back to mounting the CD changer. The side brackets are removed from the changer and loosely bolted to the base bracket bolts protruding through the carpet. The protocol converter can now be mounted between the side brackets (or any where else in the area, as long as it can be plugged into the changer) with sheet metal screws (make sure that the screws don't impale something like a wiring harness or gas line). The changer is attached to the side brackets and they and the base bracket nuts are tightened.

This picture shows completed mounting of the changer, but the changer cable has not yet emerged  form under the carpet.

Reassemble Interior

As they say "reassembly is just the reverse of disassembly", which is true especially if you kept track of the items removed and stored them in order (assuming that you garage is bigger and neater than mine :-). But several specially cautions should be observed:

And this is what the (almost) finished installation looks like:

This picture shows the installed changer and reinstalled driver's seat (the pinkish blob behind the changer is just a towel stuffed in for background). When this picture was taken the Mercedes CD changer cable was still on order (so I got lots of practice with the procedure described above :-).

And it works! (also it has not skipped), So for 1/2 of the cost of the 6 disc Mercedes changer stuck way back in the back of the vehicle, under all of our gear, we have a 8 disc changer (that is mounted a lot more solidly). But  AUTOTOYS.COM also offers a 6 disc changer that will mount in the stock location (and you don't need to buy a new CD changer cable, just the brackets).

Cost of Installation
Item Cost Vendor
Panasonic CX-DP801EUC US$ 275.00 AUTOTOYS.COM
Peripheral Electronics MBZPIL  included AUTOTOYS.COM
Mercedes Benz 163-540-31-05 US$   52.20 Smythe European


US$ 327.20
6 hrs bumbling amateur labor "free"

Back to ML Stereo Page

Back to Our 99 ML320 Page

last updated 1999-03-04