MY AC BLOWS... Literally!!

[Silver Bullet]

Hey guys... I'm still having a problem with my AC system. When I hit my "MAX AC" button, it starts blowing warm air. A mechanic from my work looked at it quickly last night. He checked my fuses, and they were fine... He checked the high temperature switch, and that was fine also. While looking at the compressor when the "MAX AC" button is on (The clutch is NOT engaging). I turned off the engine, and with a long screwdriver was able to turn the clutch manually without strain. I don't think it is locked up. I actually bought the AC compressor w/clutch brand new last year. Any ideas what I should check now?? I want some cold air dammit!! I'm sweltering down here "LOL" (Missouri)

Take care, and talk to you soon

<small>[ May 12, 2003, 12:34 AM: Message edited by: Silver Bullet ]</small>

 

[projectSHO89]

First check the refrigerant charge.

If it is ok, then check the clutch pressure cycling switch. I've gone through two of them since last spring.

Steve

 

[Zap]

I hate to ask this, but what type of compressor (brand & new/rebuild) did you get? Some compressors are notorious for failing after only a year or two of service.

Also, (for everyone's info) it is best to run your A/C for a few minutes every couple weeks (even in cold season) to cycle the oils in the system.

Additionally, if the clutch isn't engaging at all, the system may have lost enough refrigerant to keep it from turning on.

~Chris

<small>[ May 10, 2003, 11:29 PM: Message edited by: Zap ]</small>

 

[Rob94]

I agree with Steve. I went through quite a few cycling switches myself.

 

[drdave]

You can easily jump the low-pressure switch to see if the clutch engages, but be careful. If you're low on charge, you're low on oil as well. I wouldn't run it jumped for long. Have some gauges connected to get a really quick reading. You can also take a static reading to get a rough estimate of how much charge you have.

Alternately, you can just introduce 12-volts to the clutch to the coil to see if it pulls in.

What refrigerant are you using?

BTW: Was the compressor you put in last year new in the box, or remanufactured?

 

[rangerj]

SB,

Do a pressure test. The low pressure switch will not "turn on" when the pressure in the system is low (about 20psi). If the pressure is OK, then the low pressure switch can be tested by jumping the connection.

If jumping the connection engages the compressor then the switch is bad. The compressor clutch coil can be tested by connecting a battery to it. It should turn into a magnet, because that is what it is.

Did you replace the accumulator(filter) dryer, and flush out the rest of the system, when you replaced the compressor? All of the debre from the old compressor is in the accumulator/dryer and in the rest of the system.

If your pressure is low you have a leak. Fix the leak before recharging the system. Look for the black oily wet spot. check arround all of the connections first. Then check the condenser for "wet spots". Lastly check the evaporator core behind the glove box. rangerj

 

[projectSHO89]

FYI, the cycling switch is designed to open at around 20-25 psi descending (adjustable) and to close back up once the pressure reaches 45 PSI ascending.

Lastly check the evaporator core behind the glove box.

Wait til he tries to THAT!

Steve

 

[Silver Bullet]

Thanks for all the helpful suggestions guys... I have a stupid question now. Where the heck is the clutch pressure cycling switch, and how can I check it?? Also... Is this thing also called the "Low Pressure Switch" too?? I'm going to check the refridgerant pressure today. I am almost positive I have the R-12 stuff. I'll keep you posted thumbup

 

[projectSHO89]

Yeah, same thing. It screws into a bung on the top of the accumulator can. On an ATX that is near the firewall. On an MTX, the accumulator is located below the battery next to the radiator.

If your service ports have screw-on connectors like a tire valve, it is still an R-12 system.

Steve

 

[Silver Bullet]

Thanks Steve...You're always very helpful. I appreciate that wink