Damn it where's 7th gear when you need it?!
Its the programming on the early B6 climate control modules, only option would be to slap one in from a later model B6 that goes below 18, but it probably wont work with the rest of the loom, so you'd have to change a few other bits & make it pointless & expensive!! Best bet is to change the passenger side to Lo & keep the driver side higher, then the fans dont blast you away. Or as AndyMac says & turn the fan speed down!
A4 3.0 Quattro Sport - Gone & missed everyday!
Current road going missile.....
........Smart Roadster - arguably the most fun you can have in a car without using lube!!