I have a few problems that I think maybe related, heater blows hot all the time, viscos fan not kicking in, the high speed cabin fan not working
are there any relays I can check, I have cleaned the duo valve and checked fuses
any help or advice please

 

The electrical & mechanical parts of the duo-valve might operating correctly, however, the diaphragm may be broken (or the check valve clogged?)

 

cheers for than I changed the heater control in cabin works fine now, any idea on viscos fan not kicking in

 

You are referring to the fan clutch?

Overtime, the mechanism in there maybe binding. There are diy videos explaining this and how to repair it, OR just replace it. It's an easy DIY.