92 Ls 400 A/c Problem

[bpeesy]

I have a 1992 LS400. I am having an issue with the A/C. The compressor will not engage when I hit the button the compressor will not come on. If I jump the compressor by sending a wire directly from the positive batter post to the compressor, the air blows ice cold. Before jumping the compressor, I added 2 cans of freon (- had already been converted to the 134 freon). I have searched under the hood and under the dash for a fuse that says A/C with no luck. I guess in all my babble my questions are this. 1. Is there a fuse for the A/C and if so where is it located? 2. if it's not a fuse problem, what else could I do to remedy this problem? Thanks

[nemisis]

I would start by taking it into a shop to get the a/c system leak tested, because the compressor won't run if there is not enough refrigerant. The equipment to leak test, recover the refrigerant, and put new refrigerant in is very expensive and cannot be done at home. If you would like to save money you can ask them where they found the leak and take it home to fix it yourself, and bring it back to them to refill it with refrigerant. They probably won't like to tell you since they'll lose out on more money but it never hurts to ask. also when you go to fix the leak cap off either end of the open line and replace the dessicant container whether it be an accumulator or dryer container.

[wwest]

Something is wrong, very wrong. I don't think it is possible to add that much "freon" to a normally sealed system without the compressor running to provide enough suction to move the additional freon from the low side to the high side. I suspect you were somehow adding freon into the great beyond via HUGE leak.

[LScott400]

I have a 1992 LS400. I am having an issue with the A/C. The compressor will not engage when I hit the button the compressor will not come on. If I jump the compressor by sending a wire directly from the positive batter post to the compressor, the air blows ice cold. Before jumping the compressor, I added 2 cans of freon (- had already been converted to the 134 freon). I have searched under the hood and under the dash for a fuse that says A/C with no luck. I guess in all my babble my questions are this. 1. Is there a fuse for the A/C and if so where is it located? 2. if it's not a fuse problem, what else could I do to remedy this problem? Thanks

It uses the 15A Heater fuse and runs through the A/C magnetic clutch relay before going to the A/C clutch. The relay is located in the black box behind the battery. When you remove the cover, the square section nearest the fender has one round relay in it which is the A/C clutch relay. The A/C control assembly tells the ECM to energize the clutch relay. Hopefully it is just the relay.

The relay has 4 pins: #1 passenger side rear, #2 drivers side rear, #3 passenger side front, #4 drivers side front.

To check the control circuit:

With relay removed and A/C control actuated you should read 12V with a voltmeter down in the relay block between pins 1 & 3.

To check the relay:

Connect battery positive to pin 1 and negative to pin 3. You should have continuity between pins 2 & 4 if the relay is good.

[bpeesy]

Thanks, I'll try that. hopefully it's only the relay, because if I jump the compressor by running a wire directly from the battery, the A/C will blow cold as it should.

[17LexusOwner]

I have been having this exact same problem with my 90' LS400. When I turn the A/C on, after a couple seconds the A/C light on the console just blinks. I saw the earlier post and checked and tested all of my relays and fuses.

I also brought it into a shop and they converted the refrigerant and recharged it. The A/C still doesn't work. My dad and I know that it is something with the compressor/clutch.

Any ideas on how to fix this?

[Reising68]

I have been having this exact same problem with my 90' LS400. When I turn the A/C on, after a couple seconds the A/C light on the console just blinks. I saw the earlier post and checked and tested all of my relays and fuses.

I also brought it into a shop and they converted the refrigerant and recharged it. The A/C still doesn't work. My dad and I know that it is something with the compressor/clutch.

Any ideas on how to fix this?

I have been working on the same problem myself. I have a 99 GS400 and when I turn the A/C on the compressor kicks on for a few seconds and then kicks off and my A/C light starts flashing. My problem comes and goes. It only seems to do it when the car has been sitting in a hot parking lot all day. Normally in the mornings or in the cooler months I have no problem. I took it to my local dealer and of course it would not do it in the morning, so they had no idea and charged me $50. I have done a lot of research and I can tell you this. There is a rotation sensor on the compressor or what the manual call a lock sensor that monitors the RPM's of the compressor and compares it to the RPM's of the motor and if the difference is to great the computer assumes that the compressor is locked up and the belt is slipping so it disengages the clutch. These are some of the things I have checked. Ohmed lock sensor OK, checked plugs and wiring OK, Checked charge OK, Replaced belt Still NG, checked all pulleys and tension-er OK. To make sure my belts were not slipping I used some belt dressing and then put a wrench on my tension-er and gave it some extra force and still no good, I used brake cleaner and cleaned my clutch still N.G. If I jump the clutch it will blow cold all day. The only other things I can think of is something is causing to much pressure on the high side locking up the compressor and causing the clutch to slip??? or maybe something else. I hate to replace my compressor and that not be my problem.

[RFeldes]

The RPM sensor connector is underneath the compressor and a little trickey to get to. I cleaned mine on the 90 LS and the blinking stopped.

[17LexusOwner]

Thanks, I will try cleaning the rpm sensor. I hope it works.