Hi, im new to this forum.. i tried looking for similar theads but i couldnt find any.. anyways i'm trying to find out why my ac does not turn on when i push on the ac on button, I drive a sedan 03 6 speed manual, the only way the ac turns on is when i disconnect and connect back the pressure switch with the ac button pressed on.. when it turns on that way, the air is cold and i can turn it on and off with the button, but once i rev over 1300 rpm it turns off and does not turn back on until i disconnect and connect the ac pressure switch, anyone have an idea of what it could be? Thank you

 

I'm going to guess your refrigerant charge is low due to a slight leak somweher. You'd need a set of A/C gauges to take readings and confirm.

Proper way to fix is to find the leak, evacuate the system, replace the leaking O-ring, pull a vacuum and then refill with proper oil/refrigerant levels.

Quick fix is to buy a can of 134a and top off. Keep in mind this doesn't fix the leak and it possibly may cause issues down the road as well.

 

Ive vacummed twice and refilled it to proper levels, i also replace the pressure switch because i thought that it was falty but its still the same.. i think its an electrical problem and ive checked all the wires that relate to the ac system and no luck

 

There is an ATC self-diagnostic feature, although I'm not too familiar with it's limitations.

Have a read

http://www.nicoclub.com/FSM/G35/Sedan/2003/atc.pdf

 

Thanks, ive tried this already also.. ive done all the steps and no use, the only thing i have noticed is that on the ac relay there is a weak ground but when i do the pressure switch disconnect and connect it gets gets good ground and everything starts to work properly.. maybe there is some clog or something that makes the pressure raise too fast or drop, im not sure but ima give it a try again with gauges

 

I found out what was wrong with it, it turns out it was the expansion valve that it was clogged, hopefully i have enought time today to tear the dash down to get to the evaporator and fix it..

 

I can only turn the ac button on after pressing the defroster button.

How did you find out the evaporator was clogged? Thanks.

 

A friend's dad checked with gauges and said that the pressure was spiking due to the valve. It turns out even after replacing the valve im back to where i was. I can only turn it on by disconnecting and connecting the pressure switch and then it turns off when i pass 1,300 rpm