so exactly how / why does this happen, what is it a voltage thing?
Basically, the engine produces all the power the car needs, most of which goes into moving the car down the road....But if you switch on an auxilary, some of the power from the engine is diverted to running the auxilary (in aircon case it is the compressor that is required to run) so you lose some of the car ability to move.
Basically, the more power you divert from the engine into runnign extras, the slower the car will become...
