Upgrading seats to heated

fitting front heated seats to an S Class is just a simple case of buying some seats and fitting them along with changing the switch panels on the door to accept the two stage heating switches.

The facelift switch panels are different to the pre-facelift cars but the switches are the same. The switch modules for the front seats will accept the extra little switch that is needed and all you have to do is literally plug the new switch module in and it all works once you have changed over the seats.

I did this as I said on my previous S Class (KT03 BLJ) because that too came with non heated seats. It cost me £300.00 to buy a full interior out of a scrapper (but it didn't come with switches and panels unfortunately) A quick trip to MB in Warrington and Mark in the stores managed to work out the part numbers for the correct switch panels and they were ordered and delivered two days later.

I also did the full electric heated moving rear seats into my car too as these came with the interior which was from a LWB car (a bit harder as mine was a short wheelbase car) but everything still fitted OK it was just a matter of getting the correct rear switches and panels for the doors!

There is no star coding required for either the front or rear seats but when you take out the front seats you do need to unplug the cable that feeds the seat belt pre-tensioner and that flags a fault up with the airbags. A quick trip to the dealer or indy will wipe that (or if you are in Warrington, I have the full genuine MB Compact3 star unit and could do it for you FOC)

Here is a condensed version of what it took to retro-fit the heated front and electric heated rear seats into my previous SWB 03 plate S Class. A couple of things to note first: • Prefacelift seats will not fit the later facelift cars as the seatbelt tensioners have different plugs and also the seats themselves are a slightly different shape.

• Door modules and switches are the same for both prefacelift and facelift cars

• The door trim panels which surround the switches are not interchangeable between facelift and prefacelift cars

• No additional wiring was needed to fit the heated seats to my car

The most important thing is to buy a set of seats which will fit your year of car. 1999 – 2002 had a different type to the facelift cars so choose wisely! Having read all sorts of horror stories which can happen if the battery is disconnected from the S Class, I decided that it would be easier just to disconnect the yellow pre-tensioners plug which connects to the seat. To remove the front seats is pretty easy; just 4 Torx headed bolts hold them in. The bolts can be removed using standard sockets, but I chose to nip to the local Machine Mart and bought a full set of Torx headed sockets for about £15.00. These also fit all sorts of other bolts in the car so a good investment!

• Once all 4 bolts are removed, tilt the seat backwards and being careful with the slide lock, unclip the front seat wiring loom.
• Then there is a separate yellow plug connection for the pre-tensioner.
• Having done this, get into the back of the car and carefully unclip the seatbelts height adjustment wire which clips under the seat. (This is the wire which retracts and alters the height of the seatbelts when the seat moves forwards and backwards.
• Fitting the replacement seats is just a reverse order job, just remember to put everything back including the little clip for the height wire!
• Next, remove the door panel which surround the seat switch. On the facelift, the internal plastic behind the door handle is a separate piece which clips out to expose another screw!
• Using a trim remover or a wide flat blade, remove the wooden trim piece from the door.
• Start at the fromnt and gently prise it out of its fixings; being careful not to bend them.
• Once removed it will reveal a series of Torx screws (TX20 I think).
• Remove these and the one behind the door handle and the entire cover complete with the switch and the tweeter speaker will come away. The seat switch module can then be unclipped from the cover assembly.
• This cover is now basically scrap!
• You now have to go to the MB dealers and get them to order replacements with the extra cutouts for the heater switches which are these:

The switches shown are for heated ventilated seats but the cutout hole is the same! These are some spare ones I have ready for when I find some vented seats! The seat switch in your panel will be able to take this extra heater switch as it just clips onto the contacts shown here

• Once you have installed the heater switch and obtained the two new panels from MB Or you may be lucky and get the whole interior in one go and seeing as the two panels alone will cost around £160.00 the thought of paying £400 for a complete interior is not too bad after all!

Replacement of the door cover assembly is the reverse of above and does not require any more wiring to be connected, just reconnect everything you disconnected from the rear of the switch in the same position! And that is basically it….. You will have the SRS indicator on the dashboard telling you to “VISIT WORKSHOP” but a friendly indy wont charge much to reset it or if you are in or near Warrington, I have the genuine MB dealer Compact3 diagnostic kit so can do it for you FOC.

Any other questions, just PM me or leave a phone number and I can give you a call. Also, if you need a lift with them, again call in and I’ll give you a lift with them. Now if yours is a SWB car and you get the interior from a LWB limo, you can fit the full rear seat system with heated rear seats… now that is fun; especially trying to get MB to believe you that there are rear door panels with seat switches in for the SWB cars!!

I currently have the heated ones in mine but am looking to fit the one above with the memory positions so shortly I should have the two front seat switches and the surrounds (in black) but without the heated switch (as I will need those) but not sure when I will get round to doing them. The switches with the memory buttons on can also be retrofitted without the need to star them in too!

The seatbelt unit is bolted into the side pillar of the car but there is the other end of the belt that is bolted to the seat behind the plastic cover on the outer part of the seat.