Car stalls when I turn on the heat/AC


#1

2009 Nissan Sentra automatic transmission. So I leave out early in the morning, about 6:00am and when I start the car (heat and AC start up with the car), it starts just fine, runs for about 2 minutes, and then stalls. When it stalls, all the indicator lights come on. If I during start up I make sure to turn off the heat/AC, then it will start and stay on, but the moment I turn the fan on (even if the AC is turned off) the car stalls (this is true in park or in drive, although I have not tried while the car was moving in drive). Tried running the car for about 20 minutes and same thing. Now here is the perplexing part, if I let the car sit or leave out later, like after 7:30am, then the car starts fine, there is an audible clunk when I turn on the AC/heater but the car does not stall. I’ve had the car to the dealership who tried resetting the idle but can’t get the car to do this there as they open at 8am and of course “the computer shows nothing”. The AC was replaced about a month ago, but not sure if that is related or not.


#2

Might be related to your IAC valve: it takes care of your idle speed. If it isn’t working well, your idle will be way low, possibly too low to run an AC.

The IAC usually just needs cleaning which is an easy DYI job and is an inexpensive thing to try.
It sits right on top of the engine and comes off easily by taking off a couple of bolts. You shake them a bit to get the gunk out and then spray into it with some air intake cleaner or carb cleaner before bolting it back on.


#3

How old is the battery in your '09 car? The blower fan draws a lot of current, perhaps that is dropping the voltage suddenly and causing some electrical component in the ignition system or the anti theft system to shut down the car.

Since you had the “AC replaced a month ago” it seems this problem is related to the repair. Who did the AC repair? That is the place to go for resolution of this problem.


#4

Thanks RemCoW, checked my receipt and the dealership cleaned that when they reset the idle. Maybe it needs replacement?

Uncle Turbo - it is the original battery. We have a battery tester at home so I will check it out. Although I should mention that although the car stalls, none of the electric stuff turns off, just the engine. The dealership did the AC repair which is why we took it there first. To their credit, they haven’t charged us for trying to fix this so far.


#5

The IAC hardly ever needs to actually be replaced. Usually a good cleaning will clear it up.

Our uncle has a good thought. For instance, those AC replacement people may have pulled a vacuum line off causing the car to not idle correctly.
He’s right: go there first.


#6

Just wanted to give an update. So after having it back at the dealership several times and the replaced the compressor again, the car was still doing this worse than ever. I got Nissan national service involved and after the dealership gave it some thought, they decided that debris from the compressor got into the lines running to the compressor and was floating down and building up overnight. So they replaced basically the entire heating and cooling system including all the lines/tubing running to the system and the compressor and condenser (without charge btw), and it has been running ok since, although the fan now has a slight whine to it which can’t be heard unless the radio is off. On the whole though, it’s not stalling every time I turn the AC on, so I’ll take that for now.


#7

Thanks for the update. Someone else may be able to use this, if they have similar problems.
Glad it is fixed.


#8

This is very good info in at dealer with same issue I will tell them