Why does my 2001 benz S430 get hot when I turn on the AC. The heater worked all winter without that happening.

Search for my prior solution under Nitram2. It's almost always broken wires in a 3-wire harness feeding the knobs. Toyota will skim you close to $1000 for this, claiming that you need to replace the control board. It's an easy half-hour soldering job.

how to remove driver's seat heater from MBZ S430 2001

Check the underside of your hood for a belt diagram. If it's not there, call your dealer with your VIN number to get the correct diagram.

Check the fuse box and according to the printed diagram, check the fuse for the headlights, hope this will solve the problem

Sounds as if there may be a vacuum leak somewhere, possibly behind dash causing it to switch back and forth from hot to cold and vise versa

If you have the hood up stand outside while someone activates your air off and on and see if the clutch on the compressor goes on and off while they activate the switch. If that isn't it the it could be improperly charged system or your climate control door that opens and closes for hot or air is not working properly and only stays on heat.

replace the control head

that model of mercedes did come out with daylight running lights meaning that when the key is on the headlights come on at a lower wattage. and if your bulbs keep blowing i would have the wiring checked out.

put your transmission stick to ( p ) and try to move the steering wheel right and left and pull the key out

Yes you can. Make sure you not gonna buy a ceramic pads. They are so loud. My own experiance.