All US version cars for many years have run on unleaded. Mercedes for just about forever have had vlave seats hard enough that even old ones (1970s and back) do NOT need any change and use unleaded without any problem
behind rear wheel passenger side. take out plastic cover.
sorry i dont know :/
its fuse number 53 in the fuse box under the bonnet
The fuel Pum relay is located in the rear of the car in the boot compartment, it is either green or grey and is the 2nd relay down on the C220 CDI, I have heard that it is some times located at the top.
The 2007 Mercedes-Benz C-Class runs on flex-fuel (premium unleaded/E85).
The 2010 Mercedes-Benz C-Class runs on flex-fuel (premium unleaded/E85).
Regular unleaded gasoline.
The 2003 Mercedes-Benz SLK-Class runs on premium unleaded (required).
The 2014 Mercedes-Benz M-Class runs on premium unleaded (required).
The 2014 Mercedes-Benz CL-Class runs on premium unleaded (required).
The 2012 Mercedes-Benz CLS-Class runs on premium unleaded (required).
The 2011 Mercedes-Benz GLK-Class runs on premium unleaded (required).