A few days ago a AC pipe that goes from liquid accumulator to condenser went bad. So, I replaced it. Now, when I try to fill my system with 134A the system does not charge because AC compressor clutch does not engage. It does not even make any clicking noises. I checked all of the fuses and they are fine. I have a Nissan factory service manual in PDF format that says that the AC compressor clutch will not kick in if amount if refrigerant is insufficient. The pressure sensor is located on the "liquid tank" which is on the high pressure. I might be wrong, but how will the refrigerant get to the sensor if the compressor clutch does not engage. It's really HOT in Florida and it sucks big time to have your windows open ALL the time.

Thanks guys!

 

When doing AC, you need to put the system in a vacuum to start. Then you fill it. Pro's use a machine that puts the correct quantity in, but regualr people can't do that. When you put the initail shot of refigerant in it, usually it will be enough pressure to bypass that switch. On rare occasions, you will need to pybass that switch with a wire to get the clutch going. be carefull to put in the correct amount of gas. Also most systems have 2 switches, a high pressure and a low pressure. High pressure will typically be located near the condensor, but not always. If passing the low pressure switch does not get the clutch going, bypass the other one also. Remeber when you are done to reconnect them.

I am not sure about your system, but I have been running into some newer cars which if there is a code in the BCM, will not let the clutch engage. Some cars will trip a code for low refirgerant and will need to be cleared. Again, I am not sure if this applies, but it may be something worth being aware of. Good luck