[s-cars] HVAC code gurus please

[Sam Clarkson]

Hi
93 S4
I've had no heat for a while, when it first went awry i'd have heat  
on all the time unless I went to full cold, even half a degree above  
would be back to full bake. Then no heat at all. I just checked the  
servo motor it's going. Vac is sucking and is holding fine when the  
motor is off. When I suck on the heater tap servo hose it opens and  
closes fine.
So I start the car and warm it up to pull codes the heater is now  
going!? What happened I didn't change anything?
Codes read ch1; 8.7 and 11.7
The 8.7 said to read channel 8 so depending on the temp setting in  
the cabin the readings on ch8 varied a lot.
The 11.7 said to read ch11 it read a steady 23.2 regardless of temp  
changes.
Anyone able to coach me on what's going on?
How do I clear the codes to get a fresh set of readings? Or is that a  
bad idea?
Audifans fan as always....


Sam Clarkson