Hi all, I have a 2000 (W208) 230 CLK convertible, & it has the original radio with single CD slot, it all works from the radio, but if I try to increase or decrease the volume from the steering wheel controls on the right side (+ or -) nothing happens, & I get 4 ---- in the instrument cluster in the lcd display, can anybody offer any advise on what may be the cause, all other steering wheel controls work on the left side of the steering wheel
