I've been looking for a reasonable cost fix for my drivers seat.
The seat started getting a hot spot and then finally stopped working all together. Thankfully it stopped prior to burning through the leather.
I priced a new pad but that only came with the leather cover and it was 500 bucks for the bottom alone.

My question is can I have an upholstery shop sew in a generic carbon fiber heat element into the seat and have it work on the original switch and mb circuit? There are many on the market and the upholstery shop quoted 300 bucks to do the one seat but said they would have to mount an additional switch. Is there any difference in the voltage/amperage of the oem heating element vs the new generic pads? Both are two stage/heating level systems.

Has anyone else gone this route? Any suggestions?

 

If you get the CF heat pad/element (it comes as a set and has a pad for the bottom, the pad for the back/recliner the wires and a two stage LED switch), you can DIY: look for my post in the benzworld forum.
I did it few years ago in my 2002 ML320.
You will connect the CF heat element to your original wires (under the seat) and will use the same (original) circuit/switch that you currently have.
That you got a quote of $500 from a stealership, is not unusual; but, I'm just puzzled about the upholstery shop: $300 for one seat and they say an additional switch is required, that's really weird. I don't think they really know what they quoted you.
Good luck.

 

So this fix is pretty straight forward. It took me about four hours. Seat removal simple four bolts and seat belt bolt.
Then my 03 seat conveniently has one piece plastic clips on four sides that easily come off and six plastic "plug clips" that need to be pushed out at the four corners. A few of mine broke but they are available at Ace in the assorted hardware bins for a buck a piece. Also remove seat back from seat base by removing the large torx bolts.
The pad I bought only covers the center of the seat. The original pad covers the side cushions. That is where mine looks like it nearly burned through everything. Thankfully it shorted before it went any further. The original element is sandwiched between what looks like carpet padding. My bad element burnt through the bottom melting some of my foam pad and burned through the top scarring the inside leather.
Here is were I cut a corner, I didn't want to have my seat out for a few days so instead of having my pad opened up and sewn in at an upholstery shop I just put it underneath the original pad. My backrest heats up considerably faster than the bottom pad but the bottom pad does warm well, just not as hot because of the thickness of the extra pad the heat has to move through.
After finishing I thought about it and probably could have cut away the original pad in the center and mounted the new pad right underneath and then just taped the old pad back in place. I'll try that when another pad goes dead. They give you two pads in most kits one for the backrest and one for the bottom pad. I bought a Champion brand.
The only other trick was I only pulled off two thirds of the pad by opening up the hog rings on the left side and center of the pad with two pairs of long nose vise grips. You can then pull up the pad and reinstall using the same clips. Having hog ring pliers makes install a lot quicker. I also thought you could use some heavy duty zip ties but they may get brittle over time from the heat. You have to cut three slots in the center of the pad to connect to the listing rod in the center and insulate the rod with the tape provided to prevent shorting. I checked voltage at the to wire connector to get polarity correct, clipped and soldered the old connector to the new and done. Heat on my ars again!

Not bad for a 70 buck pad set and 8 buck hog ring plier investment. A few years ago I was quoted $500 for the seat pad because on my unit the element is sewn into the leather pad. What brain trust decided on that?

 

For anyone reading this, you can also solder a piece of copper wire between where the heating element wires shorted.

Aaron

 

I don't suppose you took any pictures while repairing this did you?
Nevertheless, thanks for the write up.

 

Sorry, I went to take pics and my camera battery was dead. There is another post with some pics of the pad cover removed.
But it is as simple as the write up.
Regarding just fixing the pad w copper wire, mine was pretty bad like a 5" diameter burn that looked like there were multiple connections that shorted. I don't how the original pad is configured but I figured it was better to replace than to repair a pad that looked like it nearly caught fire. Other people have had the element burn through the leather. Luckily mine shorted out before that happened.