Hi, I have a 2003 g35 sedan. i went to turn on the a/c and noticed hot air was blowing out. i pressed the a/c button the button lights up, but still hot air. so i went to check refrigerant level and it was good, replaced the relay and noticed no engagement of the clutch. then when i supplied 12v power straight to the compressor the clutch engaged. anyone know what to do from here? any help would be appreciated. thanks.

 

bump

 

You absolutely sure about the refrigerant level?

IDK about the G, but one of my previous cars wouldn't engage the clutch if the refrigerant level was off.

If the level IS right, I guess there might be a chance it's the pressure sensor and the car thinks the level is wrong, even though it's not... just theorizing.

 

yeah level should be correct. checked it a couple times with the gauge that came with the refrigerant. do you know where the pressure sensor would be on this vehicle?

 

No clue.
Sorry man.

All I can say is try looking up and down all the A/C lines.

 

The same thing happened to me and I had my AC 'recharged' and it's fine now. It would click on and then click right off. I dropped $70 at a local shop on it. Worth a try...

 

You probably already know that our cars don't use the compressor clutch the way other cars do. The swash plate construction inside the compressor takes care of variable operation rather than cycling the unit on and off the way a clutch would. Our clutch should be engaged if the AC system is on and there is sufficient refrigerant.

My system disengages periodically as it detects a pressure fault - it is just attempting to protect the compressor. Irritating but hardly worth the cost of repair yet.

 

Low pressure switch is shown on this You tube video

 

How can charge AC if clutch doesn't run?

 

Bypass the low pressure switch with a paperclip.