I need some expert help here. I have an old C180 Merc from 1994,
vintage already. Works ok, drives ok, but the aircon. has a small
problem. When I step on the accelerator while driving to go faster,
the center vent blowing cold air stops blowing and the L and R side
vents blow? When I release the accelerator, the opposite happens
and the center vents blow cold and the side vents stop blowing.
Sounds funny, but something is wrong somewhere, wiring or control
circuit? The speedometer also works, but sometimes the needle
sticks to the 0 pin like its sticky or something. Very odd, I have
considered changing to a replacement set of these dials and also
get the distance travelled down by another 100,000kms 
