My steering wheel volume controls have suddenly stopped working. Most of the searches are not a lot of help as this usually seems to happen to people who have made changes to their head unit or have never had them working in the first place.
Mine worked fine until a couple of days ago.
The horn and the cruise controls work fine, its just the volume controls.
Where do I start please?

Matey, short of replacing them not much. They are not available anymore genuine Ford so Ebay or a wrecker are the only options. BTW, series I are different to series II/III so make sure you get the right ones.

Thanks Papa Smurf. I am getting a new head unit in the next month or two is this problem something that can be repaired by a good installer?

Not really, the controls are meant to work with a Genuine radio only. Series I radios will work in series II/III and vice versa but, the volume controls will only work with the right radio for the model.
As to fixing the controls, I really don't think it is possible and if it is, I am sure that the cost would be too great.

if you take the switches off the steering wheel is it possible to open them to check for dust build up or the like? or are they a sealed throw away item?