Ann

That is all brilliant thank you! I understand the valve needs to be new and is probably the cause of the first problem. But I read that the head unit is damaged by the valve failing? Too much voltage? The heater fan noise isn't a little thing. It sets up a juddering that feels and sounds like a jet engine.. it is seriously loud.

I've only owned my S Type for about a year, a little while ago I developed the 'infamous' hot air problem. Blowing hot air regardless of temp setting. I have researched as best I can and see the fix appears to be a replacement head unit and a valve? But now the heater 'fan' is also making a terrible noise. I'm guessing that if I simply go into any garage without understanding what is needed I can expect to spend a lot of money on new parts. Are the problems linked? Will buying a new valve and a 2nd hand head unit fix the issue? Does it sound like I need a full heater unit? Thanks