Why does my ac/heater all of a sudden feel like it's got something blocking the air?

[85_305]

It feels and sounds like there is something blocking the air intake (sounds really muffled and the air output is severely decreased)? While driving, it randomly does this. So I pulled the glove box out and looked and couldn't see anything that would be blocking the intake.

After stopping at gas station and checking it out, I'm driving down the road and it magically fixes itself and it's super cold/fast again.

What is occuring?

[edsidders]

ICE

[quicksilverdon]

Originally Posted by edsidders

ICE

Possibly.
If you are low on freon (or whatever they use) the coils can form ice - the ice blocks air flow.

[CREWZIN]

...and usually it's the fault of the cycling switch (low pressure switch) on top of the accumulator. When that goes bad, the compressor never shuts off (cycles) and the "super cold air" that your talking about actually freezes the evaporator and blocks air flow.

That's only one scenario but it can happen. It did to mine. See if you can stand in front of the car with hood open and A/C on to see if the compressor is coming on/off (cycling) like it should.

[85_305]

Thats exactly what i thought was happening. What you are saying is the ice phsyically blocks the air ways though?? Which would make sense as to why if I put the regular fan on, it still does the same thing.

What if I blast the heat when this occurs next time?

I will do what you said and see if it is cycling. Thanks man

[Travis2k7]

Originally Posted by 85_305

What if I blast the heat when this occurs next time?

I'm not an A/C repair man and haven't had issues with my car's A/C yet, but I can say that the A/C at home started freezing up last year, and blasting the heat did little good against 3/4 of an inch of ice.

It was low on freon.

[CREWZIN]

Originally Posted by Travis2k7

I'm not an A/C repair man and haven't had issues with my car's A/C yet, but I can say that the A/C at home started freezing up last year, and blasting the heat did little good against 3/4 of an inch of ice.

It was low on freon.

True, against 3/4 inch of ice, but usually there isn't that much in the car. Putting on the heat does help (but when it's 90 degrees outside that sucks) and even not using the A/C for awhile will let it defrost enough to work. At least that's what happened to mine.

Travis could be right about it being low also but 85_305 said it randomly does it so if it was low and caused the problem, it would always do it until the system was recharged. My thoughts anyway.

[85_305]

Good input guys.

Ya it only does this on occasion, seems like when the ac is ran for extended periods of time it does it; ie running around going place to place w/ the ac cranked while car running. But if I only go to a few places it seems there isn't an issue.

[quicksilverdon]

So, the longer it's on, more likely to happen? That sounds like icing. If it works for short hops, doesn't have time o ice up & gets to melt in between....

[85_305]

^Yep sounds about right.

So is this natural or is it the low pressure switch?