Air Conditioner

First you have to see what the high and low air conditioner pressures are? If you have too much or too little air conditioner charge in the air conditioner system the air conditioner will not work as well.

what should the high and low side pressure be? Does the car need to be at operating temperature?

No it can be hot or cold usually the pressures without the air conditioner compressor running is over 80 psi on the high and low side .

I fixed the problem it was the low pressure switch. i did a continuity test and did not pass with a pressure of 120 psi engine off. the car blow cold air now. however when the ac is on the car idles rough and the compressor turns on and off rapidly. its like the car wants to die (rpm drops) and there is no cold air. when i drive the car it blows cold air

Sounds like your radiator or AC condenser fan isn't working .

yes i checked the fan is not working when the ac is on. the pt cruiser has only one big fan to cool the radiator and the condensor. how can i trouble shoot the issue

Do you have a multi meter to do some testing?

yes i do

Unplug the fan then start up the car and turn the AC on see if you have battery voltage at the fan connector on the harnesss side.Before you do that see if the fan blade spins freely with the car off.

ok i will do that tomorrow and i guess if there is voltage the fan needs to be replaced?

Yes if you have full battery voltage new fan.

i checked voltage at the fan connector when the ac is on it was no voltage. the ac fan relay is bad because when i switched it with the radiator relay the ac fan came on. the question is is both relays are the same because i switched them and i do not remember which is which?. does the ac fan is high or low?does the radiator fan high or low?

The inside blower relay fan?Only gets used for the high speed setting only.Not sure what your asking about the radiator fan relay?Sounds like you just need a new relay for the radiator fan.

is the ac condenser fan high speed or low speed fan

It should only be one speed for the AC but since you only have on fan for the radiator and AC it could be a two speed fan.

thank you so much for your help. the problem was the relay. it has intermittent failure. now when i turn the ac on the condensor/radiator fan turn on and no more rough idle.

i have another question what should be ac pressure for a jetta 07.a friend of my friend her ac does not blow cold air(between cold and hot). her friend mechanic serviced her ac he replaced condenser and compressor. it was working fine the first week but now it blows not very cold air. the condenser fan turns on and the compressor engages

Usually the low side is 30 or under the high side is about 175psi .At the vw dealer we always replace the compressor and the expansion valve.Sounds like it has a leak and that's why it worked for a week and now it's not so cold now.