Posted by NickD on May 18, 2000 at 07:55:55: via: mfld2-76.tznet.com or 209.83.95.76
In Reply to: Re: A question for the experts posted by Warren Willingham on May 18, 2000 at 05:58:29:
one of the major problems was leaving the switch in run, engine off, alternator field would draw 3-8 amperes and even burn up besides draining the battery as there was no air flow, same with the compressor and ignition coil (if the points were closed), this, plus the blower motor (another 20 amperes on high) could discharge a battery in a hurry plus burning out such things as the ignition coil or ballast resistor as the duty cycle of the coil is only about 50% in normal operation shooting up to 100% with the engine off, new electronics greatly reduced these currents and some compressor coils are on a timer to deenergize them when the engine is off, but that still doesn't solve getting a puddle of water on my clean garage floor if I leave the ac on until the car is turn off, and the thought of leaving my evaporator in a wet state with that aluminum corroding and nasty bugs growing on it, tells me to turn it off first before parking the car using the blower motor to dry it.