06 grand caravan, front and rear a/c. What controls the idle with a/c on? The rpm stays the same on or off. Does the computer keep rpm constant?

 

Yes. The PCM detects the A/C was commanded on and responds by commanding the Idle Air Control (IAC) valve open allowing a higher volume of air to bypass the throttle plate in the throttle body and maintain the specified idle RPM.

 

So would you see an rpm increase or does the rpm remain constant

 

remains constant. Why?

 

My wife uses the van for work, Town is only 15 miles long so alot of short trips in a day. Running the a/c constantly, most of the time the trips are not long enough too even cool down the van up front. So i am concerned that the battery is not getting enough of a charge. Its 107 degrees again today. It seems like an early summer ,but this is normal in the Arizona desert.

 

Running the a/c will have no affect on charging the battery. The 107 degrees might....lol

 

You might see a slight blurp in RPM when you turn it on but idle RPM should recover immediately.

Might consider a trickle charger or just check the static and charge voltage at the battery now and then.

 

Ok. Thanks for the quick reply, will do . Have a good day!