The repairs keep coming. Last Sunday when the forum went down I embarked on a mission to change my Airconditioner R-12 to R-134 . I had broken the metal tubes that came from the A/C Compressor about two years previous. I had always thought this would be a simple operation, but it has proved to be much more than anticipated. I replaced the hoses, oriface and the dryer. I had the system evacuated and "super vac'ed" I began charging and the compressor kicked on twice for about 6 seconds. Then the system stopped taking refrigerant and the gauge went to a little less than 100 lbs on the low side.

I cant get the compressor to come on. When I try to jumper it, the engine dies like the key has been shut off. The compressor turns by hand freely. I am at a loss. Any ideas?

 

Two wires going to your dryer or accumulator the same pull off jump the two wire with one wire. On ac never go by MFG- On how many pound or oz, to put in. go the reading on your gauges. The high side should be around 2.2 times the outside temperature, the low side the lower the better 20-40 pounds good.Everyone has there opinion about the M.F.G.. But i have been air conditioning for 29 years.

 

I would love to talk to you about this. I do not have gauges that go to both sides. This was a kit that I got at Auto Zone. I would be glad to provide a phone number or call.

Frank

 

I prefer the pressure method myself, but system capacity is 2.25 lbs of R12 which is 3 12 oz cans. For R134, you want no more than 80% of that amount, so 2 cans plus a tad should be sufficient.

Once your '92 is empty, the compressor isn't going to run until you clear the low gas code - so disconnect and reconnect the battery. The vacuum you had pulled should (have) suck(ed) in the first can and after that's done, start the engine and prop the throttle open so it's running at 1500 RPMS. Turn the a/c on high, have your next can hooked up to the charge hose, but the valve closed, and then disconnect the low pressure switch connector that's either on the outlet from the evaporator or a separate port on the accumulator. Jumper the harness terminals with a paper clip and the compressor should kick on. Open the valve and let it suck in the second can. At this point, stick a thermometer in the center vents (a digital meat thermometer from your local grocery store will work as well as anything you buy at your local discounter) and see what the temp is. A lot is going to depend on the outside air temp, but if it's 80 degrees out, low to mid 40's would be an indication that the charge is close. If it's 90, expect higher vent temps. Let the engine idle normally and plug the low pressure switch back in. For an 80 degree day, you should see 28 to 32 psi on the low pressure gage. If it's there, disconnect the blower motor so that the pressure will drop. The compressor should then kick off at 25 psi. If it does, disconnect the low pressure switch and turn the adjustment screw between the terminals a 1/4 turn counterclockwise and then plug it back in. Keep doing this until it cuts off at 22.5 psi.

Without a manifold gage set, it's really difficult to get it exactly right - if you're satisfied with it after 2 cans, I'd leave it alone; otherwise, you probably could add a 1/4 of a third can and not hurt anything.

 

SUNCR is correct. Once the system is low on freon, the computer trips a 66, and/or 68 code. No matter what you jump or if your system is full or not, your A/C will not work again until you reset the codes (disconnect neg battery terminal) If you hold the up and down temp arrows on the A/C controller, you can enter that units diag mode too. You would also find a error code in that as well. You won't need to do this though (you'll know theres a tripped error already because whatever button you push, it will flash on the controller).....

However, if you are wanting to manually engage the compressor, you can do this for freon-filling purposes. You need to ground one of the two wires on the "clutch cycling switch" coming off the Cold or "low" side of the evaporator. Don't worry, you can't short it out by grounding the wrong one (its a ground loop anyways). I DISAGREE WITH SUNCR about jumping with a paperclip. The A/C contoller controls the ground of that switch, once the controller picks up the error code, it will not allow a ground. Hence, jumping with a paperclip will not actually ground and nothing will happen when you do it. You have to provide a ground. I loosened one of the blower screws on the housing and attached a wire there, then, ground the switch plug wire. There's only two wires and they are both ground wires, but only one will work (remember the other one will stay open regardless of ground courtesy of the controller). This will engage the compressor. Just wanted to be clear....


The compressor will cut it imediately and stay on until you disconnect the ground wire. The problem with that is you do not have a high pressure set of gauges and you won't know if you are over pressuring the compressor. It shoudn't be too much of a problem though if you just want to top off a little r134. You can go by your Autozone gauge. Just remember you only need about 2 1/4 cans and you'll do fine with the one gauge

PS make sure you are adding oil with your 134a charge....

 

I did the same thing on mine. Charged and it wouldnt work. When I posted here on the CF I was told to clear the code by unhooking my battery for a couple minutes. Hooked it back up and it worked! Cooled like a arttic breeze!