Quick history: nasty surprise in NOV-2007 with my 2002 ML320 [of course no warranty any more] ... black burnt mark on my beige driver leather seat [from a short circuit from the bottom heating pad]. The seat back is OK [thank God]. A Technical Bulletin from MB acknowledges the issue, however no recall just because no car went up in flames yet. The total number of occurrences is big [from what I could get from the internet and various forums].
The stealership quoted $700 for the cover assy. [leather cover with heater pad attached] + installation. Quite expensive, letting aside the fact that colour and visual aspect of a new leather cover won’t 100 match the seat colour and aspect of my ML320 other leather seats after 5 years of daily use [a shade of beige] ...
I ended up buying an aftermarket set [bottom and back heating pads with wiring, cables, switch, fuse, etc] from eBay for $75 [with free shipping]. The width of the heating pads fits perfectly in between the longitudinal steel rods that are underneath of the leather cover.
Found some instructions for DIY on the forum and put it my self. I did just the bottom since the back was working fine. It's not hard but is not that easy either. You don't need to take out the whole seat.
Here are the main steps [sorry, I forgot to take pics]:
1- just slide the seat almost all the way towards the steering wheel
2- lower the back rest
3- remove key from ignition
4- check for side air bags [if present then I recommend disconnect the battery now]
5- unscrew 2 side screws that keep in place the side plastic moulding
6- undo the side plastic moulding [careful with the front where a hidden tab keeps the side and front plastic mouldings together
7- unplug the cables from the seat switch assy. [from the side plastic moulding]
8- undo front+side+rear holding pieces of the leather cover [underneath of the seat frame]
9- remove [carefully; it’s hard to take them out in one piece] the 2 plastic clips from the rear of the seat
10- release the 2 screws that keep the back seat together with the bottom
11- unwrap the seat cover just as far as I thought is would need it
12- cut the hog rings that hold the cover steel rod attached to the plastic wired moulded-in into the foam [you need good pliers]
13- follow the instructions I received together with the heater pad set
14- mark the line for cross steel rod
15- make 3 little holes into the heating pad in between the heating net [the instructions are calling for 3 big holes - these heating pads can actually be cut to accommodate a different/shorter seat length or to accommodate holes – how cool is that!] for the attachment points for holding the cross steel rod to the cross plastic wire
16- position the new heating pad in the proper position on top of the foam, underneath of the original heating pad
17- attach with plastic straps [that now are replacing the hog rings] the steel rods to plastic wires in the previous location of the hog rings [3 places for the cross steel rod thru the heating pad and 4 places for the longitudinal steel rod right beside the new heating pad - I didn't disassembled the other longitudinal steel rod close to the middle console
18- properly fixed the front and rear of the new heating pad onto the foam with the existing adhesive strip at both ends
19- locate the original electrical wires that go underneath of the seat to the original switch
20- cut the original wires at a convenient length
21- cut the new electrical wires at a convenient length
22- connect new heating pad to the original electrical wires that go to the original switch box [and insulate connection sections]
23 to 34- from now on assemble everything in reverse order from step #11 to #1
35- check fit and function [fit for the leather cover and function for the seat bottom and back adjustment and proper function of the new heater pad – it may take just a minute longer to feel the heat just because the old heating pad is very thick]
It took me about 1 hour but you have to have everything prepared and know every next step.
Sensitive steps:
#6 - if you break the tab you lose one attachment point [somehow still OK]
#9 - if you damage/break the clips you need to get new ones.
Tricky steps:
#12 - hog ring are hard to cut and pieces need careful removal [a magnetic tool comes in handy]
#15 - I didn’t want to affect the heating net
#17 - a second person is very helpful otherwise the leather cover will obstruct you view
#18 - working on feeling only
#19 to #22 - cramped space to work
This list is merely a presentation of what I did and is not meant to be a guide to DIY. I cannot be held responsible, accountable and liable for anything that may go wrong following above steps.
As for that damn burnt hole … I’ll keep you posted.
The stealership quoted $700 for the cover assy. [leather cover with heater pad attached] + installation. Quite expensive, letting aside the fact that colour and visual aspect of a new leather cover won’t 100 match the seat colour and aspect of my ML320 other leather seats after 5 years of daily use [a shade of beige] ...
I ended up buying an aftermarket set [bottom and back heating pads with wiring, cables, switch, fuse, etc] from eBay for $75 [with free shipping]. The width of the heating pads fits perfectly in between the longitudinal steel rods that are underneath of the leather cover.
Found some instructions for DIY on the forum and put it my self. I did just the bottom since the back was working fine. It's not hard but is not that easy either. You don't need to take out the whole seat.
Here are the main steps [sorry, I forgot to take pics]:
1- just slide the seat almost all the way towards the steering wheel
2- lower the back rest
3- remove key from ignition
4- check for side air bags [if present then I recommend disconnect the battery now]
5- unscrew 2 side screws that keep in place the side plastic moulding
6- undo the side plastic moulding [careful with the front where a hidden tab keeps the side and front plastic mouldings together
7- unplug the cables from the seat switch assy. [from the side plastic moulding]
8- undo front+side+rear holding pieces of the leather cover [underneath of the seat frame]
9- remove [carefully; it’s hard to take them out in one piece] the 2 plastic clips from the rear of the seat
10- release the 2 screws that keep the back seat together with the bottom
11- unwrap the seat cover just as far as I thought is would need it
12- cut the hog rings that hold the cover steel rod attached to the plastic wired moulded-in into the foam [you need good pliers]
13- follow the instructions I received together with the heater pad set
14- mark the line for cross steel rod
15- make 3 little holes into the heating pad in between the heating net [the instructions are calling for 3 big holes - these heating pads can actually be cut to accommodate a different/shorter seat length or to accommodate holes – how cool is that!] for the attachment points for holding the cross steel rod to the cross plastic wire
16- position the new heating pad in the proper position on top of the foam, underneath of the original heating pad
17- attach with plastic straps [that now are replacing the hog rings] the steel rods to plastic wires in the previous location of the hog rings [3 places for the cross steel rod thru the heating pad and 4 places for the longitudinal steel rod right beside the new heating pad - I didn't disassembled the other longitudinal steel rod close to the middle console
18- properly fixed the front and rear of the new heating pad onto the foam with the existing adhesive strip at both ends
19- locate the original electrical wires that go underneath of the seat to the original switch
20- cut the original wires at a convenient length
21- cut the new electrical wires at a convenient length
22- connect new heating pad to the original electrical wires that go to the original switch box [and insulate connection sections]
23 to 34- from now on assemble everything in reverse order from step #11 to #1
35- check fit and function [fit for the leather cover and function for the seat bottom and back adjustment and proper function of the new heater pad – it may take just a minute longer to feel the heat just because the old heating pad is very thick]
It took me about 1 hour but you have to have everything prepared and know every next step.
Sensitive steps:
#6 - if you break the tab you lose one attachment point [somehow still OK]
#9 - if you damage/break the clips you need to get new ones.
Tricky steps:
#12 - hog ring are hard to cut and pieces need careful removal [a magnetic tool comes in handy]
#15 - I didn’t want to affect the heating net
#17 - a second person is very helpful otherwise the leather cover will obstruct you view
#18 - working on feeling only
#19 to #22 - cramped space to work
This list is merely a presentation of what I did and is not meant to be a guide to DIY. I cannot be held responsible, accountable and liable for anything that may go wrong following above steps.
As for that damn burnt hole … I’ll keep you posted.
