Suddenly NO A/C in my 91 NA ?!

[AuroraGuy]

I have never had any issue with my AC in my 91NA.
I had the charge checked last year, and it was perfect and 2 weeks ago, it blew ice cold air.

Today I tried and nothing!

I pressed the AC button and it shows 'green' but I noticed the following:

1. Idle does not increase
2. Radiator fans do not spin up when AC is activated(like they used to)
3. I do not hear any click out of the compressor when the button
is on/off/on/off inside the car.

So something is COMMON here but not sure what ?!
Its like nothing at all related to A/C works.

Any thoughts come to mind or where I should start checking?

[AuroraGuy]

Well here is what I did so far.

I checked the pressure switch located in the frunk but just infront
of the evap box. It has 0 ohms (continuity) right now.

if I unplug the switch and turn on the iginition, the rad fans go nuts.
With the pressure switch connected - they are quiet.

Looking at the BGB (AC-42) what does this 'continuity' mean?

They list 2 pressure switches (confusing) but based on 'continuity'
it "appears" there should be adequate charge - unless I am misunderstanding.

Dual pressure switch: More than 33psi or less than 299psi = CLOSED
High pressure switch: unclear to me.

From the way I take it, this switch should be 'open' if the system has too little or too much pressure. - ie: system empty, switch = OPEN or no continuity...

I know I need a test flange - but in the mean time I was hoping to possibly determine something from reading the pressure switch.

The odd part? - with the system connected, the pressure switch is closing its contacts right now. If this works like GM's systems, when its contacts are closed, there is pressure (not too much or not too little) - If I remove the pressure switch connector - it no longer can complete the circuit yet nothing changes but for the RAD fans spinning....so I would presume that this would tell the amp that the system has high pressure and needs additional cooling - therefore turn on the fans.

At this point, I think its safe to assume based on this paultry test, that as far as the switch is concerned - the system HAS pressure.

Any thoughts on that guys?

[ModifierMR]

check your condensor (in front of the radiator) make sure a rock didnt puncture it cause you may have a leak.

[stagnot]

I am new to this form so I dont know how to attach my thread. I too am having an A/C problem. I push the A/C buttom and the engine speeds up, but the compressor will not turn on. The system was about a can low. I found the equipment to charge the system. I jumped the compressor and filled the system until the bubbles in the sight glass were gone. Every thing looked to be working good. The problem is that as soon as I take the jumper wire off the compressor the compressor stops running. Any ideas would be great.

[MR2Jedi]

Originally Posted by stagnot

I am new to this form so I dont know how to attach my thread.

Just click on the new thread icon and type away..

[sandy]

For whatever its worth..I have been chasing the ac trouble in my wifes 91 since 2004. thus far, have replaced the compressor, condenser and just this past week, the ac evap (rebuilt the damn thing with new O rings. that was a real pain...system still will not hold pressure. no leaks in the lines. definatly a leak in the evap assembly although I apparently didnt fix it with my "rebuild" almost ready to call it quits as this stuff gets expensive. the switch in the evap core (replaced it with a toyota switch) was 45 bucks alone..really, an engineering problem of some sort. replacement of the condenser (up front) LOOKS easy, its not.
You need a guage set, sounds like your refrigerant charge is low or gone completely....this is why your compressor is not cycling.