Driver Seat Recliner Knob

My driver seat no longer reclines because of this knob - I "borrowed" the one from the passenger seat so I could adjust it.

Anyone know where I can get this online and how much it usually costs? Do I have to visit the dealer?

Thanks in advance.

Part no. should be A1699180026 Cost should be around 10.00 from the dealer.

That part number doesn't seem to pull up any suppliers in the U.S. and when entered into U.S. suppliers searche's they respond with no matches. Anyone have a source in the U.S. or another part number?

BC61,
Call you nearest Mercedes Benz Sprinter dealer and have the order the correct part (traceable to your VIN#).
Have then drop ship it to you, or order it and when it comes in mail/FedEx/UPS ship it to you.
I checked, and this is the correct part number (checked against your VIN#
for the hand wheel that adjusts the back rest.
See Below:
There are a couple of other hand wheels listed in the parts list for your vehicle.
1/ The lumbar support knob.
2/Seat Adjust Handle
See Below:
If you take the "A" off the part number and Google that number you get this.
https://www.google.com/search?q=1699180026&ie=utf-8&oe=utf-8
So, you save maybe $0.25-0.50 (50 cents) by buying from a US vendor, who
sources it from Mercedes Benz.
Hope this helps,
Roger