A/C was subzero then--bam--hot air


Old 07-03-10, 01:42 AM
Thread Starter
Join Date: Jul 2010
Location: United States
Posts: 2
Question A/C was subzero then--bam--hot air

Has anyone had their magnetic clutch relay go out on their A/C? And if so, when it did, was it real sudden? And are problems with clutches common??? My A/C was like a walk-in refrigerator for the 20 months I have owned my used 2003 Toyota Corolla. It was working like a champ all day I was driving around and then all of a sudden it started I felt the air getting slightly less cool a little later that day and the next time I got in the car it just blew out hot air. I took it to the dealership and they said it was the clutch and they would also have to purge and fill with freon for $530 after they charged me $98.95 to check it out. Is $530 a good price? ($82/clutch; $40/2lb freon; the balance for approx. 3.5 hrs. labor and shop supplies). Seemed kind of high.

When I had gotten my oil changed the day the A/C had gone out, I also noticed after I had driven for a bit that the tech had knocked the dial on the dash in between two settings. Could this have done something to something on the dash or the clutch or electronics? Or--On the same trip to get the A/C checked I found out that this car was in a flood (not since I have owned it) and is badly rusted from the undercarriage down when they checked the brakes (again). Could sitting in flood water knock out a clutch on an A/C? Any ideas? I am really confused? Thanks for your help!
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Old 07-03-10, 04:23 AM
Join Date: May 2006
Location: Iowa!!!!!
Posts: 3,670
A clutch can go out as you've described and the charges aren't overly high, although cheaper is better if the work is still done right.

The compressor would have to be pulled = discharge the system and recharge it. Then the clutch would have to be replaced on the bench.

If the car was a flood car it would have to have a disclosure on the sale of the car. If not there would be some legal issues.

Depending on how high the water was on the vehicle, since the compressor is mounted on the lower engine, the flood water would have a definite impact on the compressor and just about anything else at that level.

You said the car was rusted badly on the lower components. That is a good indication the flood water was salt water. If that is the case, that is not good news.
Old 07-03-10, 07:31 AM
Join Date: Dec 2009
Location: Kingsport, TN
Posts: 217
I've had relays go suddenly or intermittently. It's the relay's prerogative. It's an electromagnet just like your AC clutch.

Check to see if there is 12v present at the leads to the clutch.
Check resistance of clutch. It should be 3-4 ohms. If it's infinite, clutch is shot. If it is below 3-4 ohms, the insulation on the winding is going which can blow fuzes.

If there is no voltage at terminals, check fuse. Also check the pressure sensor which probably is located at the receiver dryer. You can easily bypass sensor or check its resistance. If it is zero, it's ok. If it is infinite, either sensor is bad or your system pressure is low.

Relay can be checked by reading the schematic embossed on its case. Schematic shows which terminals are connected when relay is activated. If you can read the schematic, you can obviate the relay to check it or you can manually activate it by making the proper battery connection, then checking the posts that should have continuity.

I've had auto AC systems quit for a number of reasons.

1. Bad clutch
2. Dirty blower switch - switch controls both fan and sends power to relay that controls clutch on one of my vehicles.
3. Blown fuse
4. Faulty pressure sensor
5. Bad sniffer fan motor that checks cabin temperature by sucking it into a tube that has a thermistor in it.
6. Bad relay dropping out when hot, then cooling off and working again for a while.
Old 07-04-10, 09:41 PM
Join Date: Dec 2001
Location: nc
Posts: 616
I'd get quotes, including the length of warranty for parts and labor, from some other shops. The dealership is usually the most expensive. You may want to consider the option of getting a whole new compressor. There is a risk that the compressor could go bad and you would have to pay for all this again. I estimate a new compressor would be around $200 more. It's a lot but something to think about.

Question...Can a shop reuse the same freon that they purge instead of charging for new freon?
Old 07-05-10, 02:27 AM
Thread Starter
Join Date: Jul 2010
Location: United States
Posts: 2
Good advice! Thank you!

Thank you, jeff67, Lawrence C and marbobj for the responses and the advice. I will take all under consideration as to how to proceed. I am also going to get additional estimates over the next few weeks. I need more info to talk to the dealership about the rust issue. Looong story. And I really need to get my A/C fixed.

I also found info about the Blend Door Actuator in my research. The air is really, really hot. That might be one of the problems caused by the dial being moved and the dealership may not have looked for it.

I will blog back and let you all know what happened.

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