9. Electric rear outer seats. With memory, heated, ventilated multi contour with comfort head rests and Isofix.
Strip boot, remove rear seats and front passenger seat along with rear carpet and remove front passenger carpet. Remove rear headrests, parcel shelf and rear seat side trims. Trim rear seat sound deadening to clearance the individual rear seat frames. Remove and replace the centre rear seat belt and all three belt anchors and receivers... This is necessary as the outer belt anchors have the fixed rear seat outer mounts bolted to them and the receivers for the outer seats are on runners to move with the seat base. The centre belt base is also different for the same reason.
Remove the pneumatic rear head rest brackets, these lower the headrests at the push of a button. Rearrange the airline for the centre headrest and refit the centre headrest bracket.
Run the wiring harness for the rear seat control ECU. This starts in the right hand rear boot and runs to the rear SAM, ground, into the cabin and across the rear bulkhead and forward to the Body Can hub under the driver's seat.
Run the wiring harnesses for the multi contour seats. One connects the rear armrest control panel to the front left fuse box and the telematics Canbus hub in the front passenger footwell. Tother connects the multi contour ECUs to the Body Canbus under the front passenger seat along with the front left fuse box. A third loom connects the ECUs to the rear seat backs. Fit the bracket for.the rear seat ECU along with the ECU and the two multi contour ECUs.
Connect the airlines for the rear seats to the existing factory connection on the passenger rear door frame.
Refit the carpets and front seat. Install the headrest motors and guide channels for the rear headrest Bowden cables along with the Isofix top anchors, (the lower anchors are welded in at the factory regardless of options. Fit the new parcel shelf with the Isofix covers and headrests.
Bolt in the seat base frames and connect the motor wiring. Then bolt in the rear seat backs and connect the motor/heated/ventilated and multi contour plugs along with the airlines then fit the seat bases.
Fit the rear armrest and frame and plug in the rear armrest. Fit the centre seat base brackets and seat base along with the upper seat back filler piece. Then refit the rear seat side trims.
Remove the rear door cards and remove the door handle trim plate. Fit the trim plate and switch panels for electric memory/heated/vented seat controls along with the additional wiring harness to connect the seat switch panel to the door ECU. Refit the door cards.
Plug in the laptop and clear all the codes out of the ECUs and programme the car for options added.
All in all, about 25 hours work.
Items required:
Wiring harnesses; £340. (A complete body harness from a donor and a new old stock harness plus some DIY but all to factory routing/colours/sizes.
Rear seat ECU; £60.
Multi contour ECUs (2); £50.
Individual heated/ventilated/multi contour rear seats, (including seat frames, armrest, centre base, leather side trims and filler plates) in upgraded leather from an S600 and correct colour. Also included the leather centre console from the same S600;
£237 plus two steering wheels a grille and various random Mercedes spares.
Rear door wiring; £50.
Rear door switches and trims; £85.
Rear headrests, comfort and matching leather, from different source; £170
Rear parcel shelf for Isofix in correct colour; £72.
Centre seatbelt in correct colour; £50.
Rear seatbelt receiver's in correct colour; £50.
Hardware; £181.
Factory Option Cost: £3,140*
Install cost: £1,345.
Saving: £1,795.
* Includes the following options:
Isofix £80.
Comfort Ventilated Rear Seats (incl Heated seats) £820.
Rear Seats, electrically adjustable outer seats £1,120.
Memories for rear seats £240.
Multi contour rear seats £880.
Doesn't include the upgraded leather cost as the car had that from new, itself a £900 option on the S500. That said, I may yet source the front seats from an S600 so the leather matches exactly, although you'd struggle to tell the difference... This would add the massage function to the front seats as well, itself a £380 upgrade to the original options.