AC Pressure Switch

[San Diego GTR]

I am trying to figure out the AC system on the GTR. I have not yet added freon to the system. Will the system pull the ac compressor clutch in when it has pressure in the system and the AC Pressure Switch sees the pressure? Right now I've got +12v up to the AC Pressure Switch but not out to the compressor.

Anyone know anything about this system?

Thanks,
Paul

[Steve_D]

With AC turned on, and fans on, 12v goes to the pressure switch. If the system is up to pressure then the switch will drop the compressor clutch and at the same time activate the AC relay which turns on the condensor fan.

Steve

[GTRCLIVE]

The "BINARY" AC switch needs to see enough pressure in the system before it will allow the clutch to come in, the switch is really a protection device for the pump and system. If the pressure is to low (No gass left in system), it will be open circuit so you wont run the Pump dry. If the pressures to high (to much gass, blockage in lines, or condenser not working for some reason) then it will also be open circuit to stop a possible bursting of an lines etc...

Basically the pressure has to be within a certain range for the system to run.....

Most normal cars have a "TRINARY" switch which also controls the condenser fan on a separate set of contacts (turns it on and off depending on another pressure range, depending on the efficiency of the air flow over the condenser ie. Highway speeds with a front mounted condenser would not normally need the fan on), but the Condenser being in such a low air flow area on the Ultima that it needs the fan on all the time, so AC fan never turns off.........

Hope you got that...

If not look at the Wiring diagram on the stickys...

[crafty]

The rear of the car is obviously low pressure and will suck air out of the engine bay. I think you'd get a lot more air through the side pods with the bottom of the engine bay closed off.

[San Diego GTR]

Thanks guys! That is exactly the kind of feedback I was hoping for. I'm taking it to get the system charged this week. Wish me luck it is heating up her in So Cal and I'll need it very soon.
Paul

[crafty]

You might want to look at beefing up the feed to the AC fan too

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

[Graham-P]

You might want to look at this thread as well.
http://www.pistonheads.com/gassing/topic.asp?h=0&a...