I have a W reg Renault laguna, and the heater is only working on setting No. 4, the highest, help if you can..

I have checked the fuses, and changed the fuse, but to no avail, but due to disability, cannot really get in to have a proper look at the back of the heater control panel, but any help would be good, and has anybody else have a similiar problem and found the fault, would be grateful for any positive information thanks.