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AC is blowing Hot???

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Old 09-08-2006, 11:28 AM
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Charley Hoyt
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Default AC is blowing Hot???

My 99 (with Dual AC) has developed an intermittent AC Problem. Most of the time the AC works fine…but for some reason the AC intermittently blows HOT. If I turn the AC Control **** all the way down it often (but not always) causes the AC to blow cold. But when I start raising the temp by just a few degrees it starts blowing cold. I checked the DTC codes and there are no HVAC Codes…but there are some codes for the IPC, LDCM, RDCM and SCM.

Any Ideas???

Thanks for the help.
Old 09-08-2006, 11:55 AM
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Guro305
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Dude I am having similar problems. My drivers side now is blowing hot and the passenger side is blowing cold. I have a 98 with basic controls, not digital.

Checked the compressor and it is kicking on. I hope we could both get some help on this.

Last edited by Guro305; 09-08-2006 at 03:32 PM.
Old 09-08-2006, 03:40 PM
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Guro305
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Ok, I ran the codes and nothing kicked up. Seems everything is ok. So what's the next step? Disco' the bat'?
Old 09-08-2006, 04:41 PM
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Most common explanation is low refrigerant. Get a refrigerant gauge, hook it up to the low pressure side, run the AC, and see if your system is low. Then, the question becomes *why* is the system low.

I had the same problem, which eventually progressed to a complete lack of cooling on either side. Leaking condenser, shot compressor (though it still ran!). Still hurting from the bill on that deal

Good Luck,
Andrew
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Old 09-08-2006, 04:42 PM
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Guro305
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I got a gauge, I'm gonna check it later. Wait, how could your compressor still run and be shot?

In my experience once it's shot it's shot. The clutch is still kicking on and off on mine.
Old 09-08-2006, 05:23 PM
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VetteMed
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The seals were shot, it was leaking refrigerant and dye all around the front and rear of the compressor, and I'm assuming that some of the internal seals/rings were bad as well, So apparently it wasn't pressurizing the system adequately.
Old 09-08-2006, 05:26 PM
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Guro305
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Ok, I understand where you're coming from now. Shot in the figurative tense.
Old 09-08-2006, 05:27 PM
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Right, as in, not seized.
Old 09-08-2006, 10:10 PM
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harrell3us
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Mine did the same thing. It was the climate control. $500 later, it works. Had to replace the whole module.
Old 09-09-2006, 12:11 AM
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Jeff Jeff
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There are quite a few reasons why it would blow hot, head units, actuator doors, vacuum lines disconnected, low freon, etc.

My '98 was blowing hot from drivers side and cool from passengers side, sometimes both would blow cool. I had the freon recharged, I was down .75 which is about 40% low. The shop wanted to charge me $1000 plus to fix it, but that is another story. I told them just to fill it back up.

Long story short, the recharge fixed my issues and it has blown full cold from both sides ever since (6 months).
Old 09-09-2006, 01:22 AM
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jrose7004
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I had a leak somewhere in my system and once it was fixed it's just fine. Cost $112.00 to fix.
Old 09-09-2006, 02:12 AM
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Guro305
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Hey guys, before I go get a reading tomorrow, what is the correct psi or the correct range of the psi for the a/c? Also, not to sound stupid because I never bothered to look, but is the low side clearly marked and if not, which one is it?

I'll keep you guys updated.
Old 09-09-2006, 09:13 AM
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VetteMed
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The low side is just inboard of the battery area -- it's the larger diameter aluminum tubing. Not sure about actual pressures, though... some of the cheapo gauges have the appropriate ranges marked on them.
Old 09-09-2006, 02:47 PM
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Charley Hoyt
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Originally Posted by harrell3us
Mine did the same thing. It was the climate control. $500 later, it works. Had to replace the whole module.

Ouch! That seems like a likely candidate to me. My issue isn't a hot on one side and not the other. The car sometimes just chooses to blow hot....and I mean really hot...like the heat is on high. I tried directing the flow to the floor, then the vents, then the defrost. Same condition....full Hot. If i turn the control all the way down to the coldest setting it starts blowing cold again. Very strange.
Old 09-09-2006, 06:19 PM
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Switchbarrel
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Default A/C intermittent

The A/C in my 2001 just started intermittently working. Some days it will blow cold, other's it will just blow whatever the outside temp. is (hot). I can still turn the heat up hotter, but can't get it to blow cold when I want.

Dealer says I need a new A/C Control Head, part no. 10345293. Hope yours is something cheaper.


-Rick
Old 09-09-2006, 06:53 PM
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Guro305
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Default Update!

I unplugged the battery and nothing. I hit the lowside with the gauge and it read fine. Once I started up the car and hit the gauge, it was obvious what the problem was. A can of freon later and alas.........ICE COLD A/C!

Last edited by Guro305; 09-09-2006 at 08:19 PM.
Old 09-10-2006, 12:41 AM
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ISeeRed
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Originally Posted by Charley Hoyt
Ouch! That seems like a likely candidate to me. My issue isn't a hot on one side and not the other. The car sometimes just chooses to blow hot....and I mean really hot...like the heat is on high. I tried directing the flow to the floor, then the vents, then the defrost. Same condition....full Hot. If i turn the control all the way down to the coldest setting it starts blowing cold again. Very strange.

It seems to me that the vacuum operated switch that shuts off the flow to the heater core is sticking. I have had this happen before and it can drive you crazy being that it is intermittent. Check it out!

Ray
Old 09-10-2006, 06:35 PM
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Charley Hoyt
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Originally Posted by Guro305
I unplugged the battery and nothing. I hit the lowside with the gauge and it read fine. Once I started up the car and hit the gauge, it was obvious what the problem was. A can of freon later and alas.........ICE COLD A/C!

That's not good. Freon does not wear out or get used up....if you need freon...you have a leak somehere.
Old 09-12-2006, 01:41 AM
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Guro305
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You are right. Used freon with stop leak/leak tracer to much success in the past. I tried it now and didn't see any of the leak tracer spill out anywhere.

In my experience that's usually a good sign because the leak is very very small. I'll leave it be until it, if it, runs out again. Sorry if I'm one of those "worry later" kinda guys!

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