Air con not working

[VenomX]

Have a C240 with 34K miles on the clock. Previous owner never used the air con.
The light stays red, which means it is off.
If I press the button, nothing happens, it stays red.

I have checked the fuses. All OK.
A friend checked my refrigerant levels and there was plenty of gas in the system, there are NO error codes at all on the OBD2 reader.

All other heating works fine, including demisters front and rear.

any ideas ?
Thanks

 

[andy99]

If the system detects low pressure it disables the a/c even if it is refilled and back to pressure. If it has been refilled after a low pressure it will need to go to a specialist to reset. Mine had to go to Merc as none of my locals could do it.

On my E-class the red light meant on. You don’t say what year your car is so can’t compare.