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Recirculating Air Problem

Posted: Thu Oct 31, 2019 6:13 am
by xyz
2003 Mitsubishi Eclipse GT, 144K miles

I was driving in the rain with the defroster on, to defog the windshield. If I'm not mistaken, I believe the AC compressor and Recirculating air were activated.

I heard a brief squeal from the engine compartment, and when I looked down, the compressor light was flashing, and continued to flash until I got to my destination.

Now the compressor appears to be working, but the Recirculating air button doesn't do anything. I don't know if it's stuck on recirculating or outside air.

Any thoughts?

Thanks

Re: Recirculating Air Problem

Posted: Thu Oct 31, 2019 7:23 am
by Cusser
xyz wrote:Now the compressor appears to be working...
Any thoughts?


Appears??? Turn on the engine and AC, visually determine if the CENTER part of the AC compressor is turning, not just the outer pulley.

Re: Recirculating Air Problem

Posted: Thu Oct 31, 2019 8:02 am
by JohnHere
Your car's A/C compressor has a speed sensor on it that sends compressor RPM data to the A/C amplifier, and so does the engine's computer (ECM). If the amplifier senses a difference in RPM between the compressor and the engine's crankshaft, it shuts off the compressor (for reasons I won't go into here) and triggers the blinking A/C light, indicating a problem with the A/C system.

You were driving in the rain with the A/C on. I think what might have happened is that rain water splashed onto the compressor, causing momentary belt slippage (stopping the compressor from rotating for a few seconds) and the squeal you heard. Now, the belt has dried off and the compressor is rotating normally again, so I don't believe there's any other problem with the system. Just drive the vehicle as usual, and the A/C should now operate as before.

As for the Recirc button, when you press it can you hear the blend door moving within the dash and feel the airflow change from the dash vents to the defroster vents and back? If so, you might just have a burned-out lamp in the button.

Re: Recirculating Air Problem

Posted: Thu Oct 31, 2019 8:58 am
by xyz
JohnHere wrote:Your car's A/C compressor has a speed sensor on it that sends compressor RPM data to the A/C amplifier, and so does the engine's computer (ECM). If the amplifier senses a difference in RPM between the compressor and the engine's crankshaft, it shuts off the compressor (for reasons I won't go into here) and triggers the blinking A/C light, indicating a problem with the A/C system.

You were driving in the rain with the A/C on. I think what might have happened is that rain water splashed onto the compressor, causing momentary belt slippage (stopping the compressor from rotating for a few seconds) and the squeal you heard. Now, the belt has dried off and the compressor is rotating normally again, so I don't believe there's any other problem with the system. Just drive the vehicle as usual, and the A/C should now operate as before.

As for the Recirc button, when you press it can you hear the blend door moving within the dash and feel the airflow change from the dash vents to the defroster vents and back? If so, you might just have a burned-out lamp in the button.


Pretty close to what I'm thinking because when I heard the squeal there was a very slight pause in the engine. That and the fact the the compressor not working (as indicated by the flashing compressor light) was temporary.

&, no, I did not visually look at the compressor, because I could feel it kicking in and out.

Just to say it, it has just turned cold and nasty, and I have had mice in the vent system before. The car sits during the Winter, and one Spring I had a nest of string and leaves and what-not in the blower. I've saved a picture, but can't figure out how to post it.

Re: Recirculating Air Problem

Posted: Thu Oct 31, 2019 9:12 am
by xyz
I just went out to check it, and everything is working.

Thanks for fixing it.

:D

Re: Recirculating Air Problem

Posted: Fri Nov 01, 2019 10:28 am
by JohnHere
Great...glad we figured it out and that it wasn't something serious (and expensive).

I know what you mean about critters nesting in the HVAC system and elsewhere in a vehicle. For cars that aren't driven regularly, I've seen them set up nice, comfy homes on top of the engine, in the upholstery, headliner, and in the exhaust system as well.

I've never tried to post any pictures here, so I'm afraid I can't offer any advice about that.