Air conditioning inoperable in 89 240sx

[Dante]

Since I've had my car the AC hasn't worked at all. Here's what I know so far:

-the fuse (there's only one I know of) is fine. -the engine doesn't bog or otherwise indicate the compressor is operating when the ac is switched on.-the light on the ac button does not turn on when the button is pressed.-there is no visible difference in the compressor's operation when the ac is on and off (IE, the center isn't turning, tapping it with a hammer does nothing). The center seems to be one piece so I'm not sure if the whole thing is supposed to turn or what (I'll try to get pics later).

Currently I'm thinking it may be either a bad clutch or an electrical issue.

I'm sure there is a lot of information on this topic, but I couldn't search for 'ac' and 'air conditioning' yielded few results. Thanks for any help.

[blues14]

I am having the exact same problem on my 89 240 coupe!! someone please help us:(

[NISTECH]

Sounds like you have a freon leak. Thats what the system does when the pressure in it is low. Unless the pressure switch sees a specific amount of pressure it will shut down the system by depriving it of a ground cicuit for the relay.

[Dante]

So if I have the freon refilled this will occur again? Is there any way I can find out where the leak is?

[NISTECH]

best way to find the leak is to use a halogen leak detector or a black light if it has dye in the system. If you dont fix the leak you will loose the freon again. R-12 freon you cant get at any store it has to be installed by a certified tech. BTW R-12 is in the neighbor hood of $5 an ounce. your car holds about 32 ounces.

[blues14]

that makes sense, cause a shop just replaced my motor and i told them to hook up the ac but not to worry about filling it. since the system is empty, can i use one of those r-134 retrofit kits they sell at the parts store?

[NISTECH]

Yes but you need to completely flush the system of any collected oil in it. This will require removal of alot of the parts to pour the oil out. Also it might be a good idea to replace the reciever/dryer

[bendychicken]

What does it mean when the low side goes vacuum?FSM says oil contam or bad expantion valve.I blew all the oil out of the system when I retrofitted. Do you think that would remove all of it or do I have to take every thing apart to remove the oil?

Many thanks.~ken

[NISTECH]

You need to take everything apart to get all the oil out.

[bendychicken]

will do.

[bendychicken]

OK, I took EVERYTHING out. rinsed everything out with acetone(except the compressor) and compressed air. Flushed the compressor with plenty of ester oil and filled to spec amount. Found a leak on a connection to the evap coil(crusted grean dye). Sanded the male end of the connection smooth with 1000grit and then 1500 grit paper. installed all new o-rings pulled full vacuum for 20 min. charged one side with 134a while vacuming from the other(just to help flush out ANY moistere). Pulled full vacuum and held closed the system of to check for pressure rise. Good.recharged with fresh 134a. test........airs cold......gauges are correct. great. I got in the car and drove to winter haven. by the time I got there(3 hours later) she was bairley blowin cold! MOTHER *@@^&**#@*&%$@^%^##^%&%()&$@$%^&. My sniffer and gauges are in orlando and I wont have access to them till tuesday.

Any ideas??

[ricebike]

sounds like u may still have a leak... sorry