Daf fans

My basic knowledge is that the rotating knob in the cab (not the driver LOL) basically is a bit like a twist-grip gear shift on a mountain bike, it pulls a little lever backwards and forwards which is just under the bonnet of the vehicle. This is like a gate which moves between hot and cold air or obviously can blend both together. Most vehicles the knob will stiffen up (!) and become difficult to turn, or in other cases if the knob turns really easily basically it’s not working. It’s failing to move the little gate widget under the bonnet. Sorry I can’t find any decent pics online. Should be an easy fix, or might just need lube.