Heated Seat: Relay or Switch?
 

The heated seat button works in an unusual way on my 02 W210. When I push the top 1/2 of the button nothing happens, no lights or heat. If I push the bottom 1/2 the seat turns on as expected in High, push the bottom again and it goes to the low setting, push it a third time and it goes off. The top 1/2 of the switch doesn't seem to do anything. Would this problem be related to the switch itself or a relay? Or something entirely different?

Can you switch the repays? On my 190, they are under the passenger floor board. In mine, they both turn on high and then time down to low. I cannot turn them on low to start with. I tried swapping the relays but the same happens on both. I have not tried a new switch as it seems weird that it would happen to both at the same time.

I'll follow this thread. May be I can learn what is screwed up with mine.

Probably a fried relay. If it's like my car, the controller with four relays is located under the driver's side rear seat cushion. Open up the controller and you're likely to find that some of the relays are fried. I replaced the relays for around $7 each.