Make sure to check all your fuses, especially whichever one controls the radiator fan(correct me if I'm wrong) because the AC being on will override the radiator fans regualr sensor?(total guess here) And I think it is normal for the rpms to drop and rise just slightly when the ac is on.....
But there is a good chance this is all entirely wrong so just wait a minute for someone who actually knows what they are talking about to respond
edit - I didn't read the part where you said the car dies when the AC is on...that is not normal.
But there is a good chance this is all entirely wrong so just wait a minute for someone who actually knows what they are talking about to respond
edit - I didn't read the part where you said the car dies when the AC is on...that is not normal.