View Full Version : a/c not staying on

07-23-2010, 02:07 PM
have a ac that will not stay on when it is hot outside. ac is completely recharged and comes on and makes a jerking feel within the car while driving and then ac cuts right back off and repeats the same process . ac works great at night or when it is not really hot outside. i have to figure this problem out and would really like some help. i have heard it may be something telling ac it has a zero duty cycle. and have also heard it could be spark plugs but car runs great with ac off.

07-23-2010, 07:36 PM
fan motor is out just had mine go a couple weeks ago...got a new one

07-23-2010, 08:56 PM
First thing is to run the on-board HVAC diagnostics and see if there are any codes.

07-23-2010, 09:13 PM
i scanned my ecu and there were no codes regarding my ac.

gaberossi, was yours doing the same thing cause my ac blows cold air at night but just cuts on and off when its really hot outside and will not stay on like the ac compressor is cutting on and off. i can also hear the ac cut on and off. car jerks when ac is cutting on.

07-24-2010, 11:49 AM
Open Hood.
Start car with cold engine.
Go stand in front and listen.
Go back into car and turn on the AC
Go stand in front and listen and wait.
You should hear the electric cooling fan running.
This is mounted against the radiator.

Do the same thing when the car is hot.
If the engine coolant is very hot the fan will run on high
When you turn on the AC it should if not already running start

The vibration you feel could be a broken or split fan blade - or it is just going out as Gabe is saying.

fan motor is out just had mine go a couple weeks ago...got a new one

If the fan checks out, the car could have a weak compressor clutch - only failing when the compressor is under a high load like when the outdoor and inside car temps are very high.

Steve Chicago
07-24-2010, 12:57 PM
If the system is overcharged, It'll be cutting out whenever the head pressure goes too high. The higher the thermal load on the system, the more frequently this will happen. (check the fan first)

07-25-2010, 01:03 PM
mine on a hot day would kick in but then shut off within 5 seconds and my car would never get cool