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Okay so bottom line, I can use the fan and the flow as long as I don't push the temperature or the fan (re-circulation)? Or is it best to just leave everything off and not touch anything like a good little boy? :D :lol:

Also Charlie, I cannot thank you enough for all the work you've done for me! And okay I will do the hood check with all AC compartments off and report back shortly if there is any noise. Is there a specific noise I should be looking for? A clunking or a grinding, or what? And the RPM thing... I'm not sure if it's just when I am stopper or in park but my RPM stops a little above the 1, like it won't be all the way down unless I turn off the car and take out the keys, is this normal?

(sorry for all the questions guys, just be nice to me!) :lol:
 

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must have been one of those fluke things. However, we have the best weather this week. I think it got down in the 50's. but back to the compressor, I guess it has something to do with de-humidifying the air so that's wht the compressor comes on on defrost. One thing I hated about the vette was it had no ac so when the windows fogged you were SOL. the heat and defrost worked but even driving it around in the rain the windows would fog up.
In the "old days" the AC only came on when AC was selected. A lot of units failed because people never turned on their AC until the first hot day of the summer. Since the AC had not been cycled on, the seals dried out and they leaked down. After having to do a lot of warranty maintenance, the engineers changed the AC on / of cycle to include on with the defrost. It is partially functional as it might help with defrosting, but its mostly to keep the AC seals happy.:grouphug:
 

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In the "old days" the AC only came on when AC was selected. A lot of units failed because people never turned on their AC until the first hot day of the summer. Since the AC had not been cycled on, the seals dried out and they leaked down. After having to do a lot of warranty maintenance, the engineers changed the AC on / of cycle to include on with the defrost. It is partially functional as it might help with defrosting, but its mostly to keep the AC seals happy.:grouphug:
That may be true as well, but the main reason for the A/C on defrost is as TX said, to dehumidify the air. It clears fogged glass MUCH more quickly. If you have a car without the auto-A/C, you can experiment with demist setting with an without A/C. Amazing the speed difference.
 

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Okay so bottom line, I can use the fan and the flow as long as I don't push the temperature or the fan (re-circulation)? Or is it best to just leave everything off and not touch anything like a good little boy?
You can use the temperature knob (turn), the fan control (turn) and vent postion (turn) EXCEPT for the far right Windshield position. I think you can use the Recirc. (push) but certainly NOT the A/C Snowflake (push).
 

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You can use the temperature knob (turn), the fan control (turn) and vent postion (turn) EXCEPT for the far right Windshield position. I think you can use the Recirc. (push) but certainly NOT the A/C Snowflake (push).
Okay T.S. thank you so much for the clarity.

Also to the forum community, would you guys care for a video or a step-by-step picture procedure in how I fix my A/C for future references? I plan on doing it myself (hopefully soon, if not I'll just wait till the air warms up a bit until March-ish)
 

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we always welcome how to videos. if you got one, send one. And Mehran, I sent you an email.
 

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With the greatest humility and respect I offer the following:

So in reality, the "pump" or compressor has no actual drying affect on the air, the compressor itself is a closed system pump, that forces gas into a compressed tube, and then upon release of the gas the tubing freezes. The a/c fan then blows outside air over the frozen tubing, which looks like a tiny little radiator, thus cooling the outside air.
During the winter, people typically do not use their a/c system (unless they live in the southwest US or someplace HOT), which basically would mean that for many months the A/C pump, tubing, condenser and other components would suffer from what's basically called "Lot Rot". Rust would build up from trapped moisture, the lubrication that keeps the pump nice and smooth would pool up and dry off the moving parts. And when the summer time hit and someone turned their A/C on it would sputter and spit and probably seize the pump. Therefore, an ingenious engineer figured out to wire the A/C system to the Defrost button, since they use very different air intakes. So you can send warm mixed air to the defrost vent, and at the same time keep the A/C system running and lubricated through the long winter months. So your A/C runs when you push defrost not to dehumidify your air, but to keep you A/C system from taking a crap in the winter.

The reason you would see an affect on fogged windows from using the A/C switch, is because it's bringing in outside cooler air, which is probably far less humid than the air you've been breathing that fogged up the window in the first place. Dry external air, whisks away the water vapor on the windows. The cooler air also has an impact on the air that was fogging the window, in that it cools the air bringing it farther away from it's condensation point and causing it to reabsorb the moisture it shed on the glass.
The defrost system, is of course by name designed to get rid of "frost", but it also uses outside air mixed with heated air to give you the same affect of removing fog. However, not only does it bring in external dry air, it also brings the temperature of the glass up, which changes the condensation capability of the air on the glass.

Take your mind back to last summer, when you had a nice cold beer on a hot day, the can sweats, water drips off the cold can because of condensation of moisture in the air on the cool can surface. Think of your cold windshield, it's probably just as cold as that beer, and the air you are exhaling and sitting in is warm and juicy, so the glass fogs up. You can either heat the glass, cool the air in the car, introduce dry air to the car, or pull over and get a beer. Basically, I would suggest that the defrost feature offers two of the 3 viable options, it heats the glass, and it brings in external warmed dry air directly onto the glass to whisk the moisture up and prevent further condensation. The A/C option only brings in cooled dry air. Which works faster? maybe A/C does or maybe not, I think it depends on how warm your engine is, since A/C can be cold in seconds, but heat takes many minutes to manifest. I think the better question is which works longer and is more comfortable, I think that's definitely the defrost.
 

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And


/C operation:
The A/C operation described above is a bit unclear. Refrigerant is compressed to around 100psi as a gas (today its r-134a) by the compressor. Then, this gas is sent to the condenser which cools the high pressure, high temperature gas into a lower temperature gas. This gas turns into a liquid by the time it leaves the condenser. This liquid (highly pressurized) is sent through tubing until just before the evaporator it is sent through a fixed orifice that quickly depressurizes the liquid and quickly turns back into a gas. That is, it evaporates. When this refrigerant evaporates, it absorbs heat; thus, we get a cold sensation. Since the boiling point of r-134a is around 35 deg f, the air around the evaporator will be about 35 deg f. As the gas evaporates in the evaporator, a blower motor blows air across the evaporator and sends this cold air (about 35 deg f) into the passenger compartment. Thus, cold air.
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A/C as a dehumidifier:
The A/C does dry the air, but only in warm temperatures (i.e. you will see the moisture dripping from underneath your car). This moisture comes from the evaporator drain (which is inside the passenger compartment). So inside air is actually being 'dried' in the warmer months. So, the above statement about the A/C not drying the air , however, is true only if it is cold out.
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A/C bringing in outside air:
The A/C system doesn't necessarily introduce outside air. The blower motor is inside the vehicle and blows inside air or outside air (depending on the recirculation door position) across the evaporator, then the heater core. Thus, if the A/C is on and the recirculation door is closed (closing off outside air) then no external air is introduced, and defogging doesn't occur. BUT, if your car lets you turn on defrost (which always brings in outside air) and ac, then of course, external air is introduced. So, although technical points, I add these facts. Thanks to whoever posted the above "Correction" piece as I learned a lot from it. Thanks, and I hope my little piece shed some light.
 

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Yes Rob it did help my understanding to the whole A/C cycling. Also for those who care to look at my diagnosis on my A/C issues and give possible solutions, I am going to add a video I just took about checking out my car to my previous thread. Thanks in advance everyone!
 

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wow, thanks for the breakdown Rob. Everything you wanted to know about air conditioning but were afraid to ask.
 

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lDry external air, whisks away the water vapor on the windows. The cooler air also has an impact on the air that was fogging the window, in that it cools the air bringing it farther away from it's condensation point and causing it to reabsorb the moisture it shed on the glass.
The bold part is not correct. Parts of the other post are misstated as well :/

Evaporation is a cooling phase change... It absorbs heat from the environment (think of your sweat). I believe he said that part right... But condensing is a warming phase change. The tubing from the compressor to condenser (most hot) and condenser to the orifice (less hot) is the hot side of the system.

Anyway...

Simply cooling air does not move it further away from its condensation, or dew point. It increases condensation tendencies because the air becomes more dense and cant hold as much water vapor (making the water vapor much more likely to condense on any available surface, IE dew, or condensation nuclei, IE fog).

AC has a drying effect because the colder/denser air can't hold moisture as well as hot air. The air condensing effect happens at the evaporator (the part you notice dripping in the summer) and it happens in winter or summer. It's only more noticeable the bigger the temperature change (summer), and the higher the humidity (winter with several humans puffing out humidity into the car).

*** Slightly off topic... (As if this whole side track wasn't already)

You can find discussions of this regarding home AC systems and oversized units. Contractors put in oversized units so that the house can be cooled faster. However, because the units run for less time, they remove less humidity from the house. That in turn makes the occupants want to turn the AC lower.

Conversely, the same occupant would feel more comfortable in a house cooled by a smaller unit that has to run for longer periods of time because it will dry the air more. However, at a lower temperature setting, it will turn on far less often.

IE, smaller unit set to 76/77 runs for 15-20 min once an hour versus a big unit set to 75/76 that only runs for 5 min, but runs every 20 min (and consumes more electricity when it runs).

*** Back to autos...

You can prove it by running AC in recirculate mode. Initially it will defog the window. Actually, it will continue to defog the inside because the air is dried out or at least drier than the air coming out of our lungs and hitting the windshield. But lowering the temperature of the glass only complicates the problem on the outside and on the areas of the window not being hit by the drier air :/

Back on topic...

I think I will pass on $90 of wiring crap thats probably just going to burn out again anyway. (Searching for the soldering iron and something good to seal up the whole thing :/
 

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I hope, but I just read this again and I assume my hunt is still not over, I ordered the harness but missed the wording that the resistor was a separate part, well back to the web.

EDITED TO ADD Resistor Information - gmparteast has the resistor. They do not give the total part number, but what they do give is **397098 RESISTOR BLO MOT

They still show the old part number for the harness, but they do have it, if you use the new number above.
the full part number for the resistor
P # 10397098 IS THE CORRECT P# FOR THE VIN # PROVIDED. Gm Catalog has a user notes that states when replacing resistor you will also need connector p # 13586175.
 

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Thanks for the below info that you posted on 12-28-2012, I added water to the radiator as it was low and then my AC interior fan started working again. I was troubleshooting like crazy and would have never figured that out.

UPDATE: Ahhhh, I just noticed something else. Power to the motor is supplied via the HVAC relay (#30 in the BCM). That relay is energised by some logic which (apparently) depends on the coolant level sensor. Are you sure your coolant level is good (or that sensor, or its wiring, is not suspect)? Also check that HVAC relay, make sure it's not loose.
 

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hey everyone, regarding the "blower going out".....check this out then give me some ideas....ok?...Thanks...... blower stopped, checked all fuses, both locations, fuses good....pulled hvac fuses downstairs and watched the lights dance around, blower came on for a little while but air was hot, noticed a yellow light on cluster that showed the car with a padlock placed through the middle??.....turned car off, restarted, light goes out, blower kicks on, ac starts to get cold.....good for two days.....go to work with ac, 2 oclock leaving, no blower, I reach over, open glove box, reach in with my hand and bump the motor with my fingers, it starts blowing no matter what speed I have it on....I have done this twice now......past two days......ac in morning, no ac in afternoon........bump motor with hand, comes right on......motor isn't loose, connections feel tight, and I do not smell at any time anything burning or melting....(I have experienced that a few times over the years so I know the smell)...... I replaced the relay downstairs thinking that was the problem, happens with old or new one....anyone have any troubleshooting tips for me to do this saturday morning??......I'm going to pull the resistor and look at the connections....but what I don't understand, is the first time I bumped the motor, I just barely tapped it with my fingertips, and voila, it came on no issues.........any help greatly appreciated as, yep you guessed it, temps are in the 90's here....so NOT a good time for this crap..... Thanks a mil everyone!
 

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Nocell - I understand you're cross-posting across multiple sections in an effort to solicit an answer, but it is counterproductive. Members will not want to respond in multiple threads and will opt to not respond at all. Not trying to be a jerk, just trying to keep the responses and the knowledge base in an easily "locatable" location.
 

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So mine motor just starting making a loud humming noise. Is it on the way out, should I replace it? When it first started I thought it was some kind of feed back through the speakers. It sounds just like that low frequency ignition hum you might get in an older car when it's not shielded properly.
 

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Blower just stopped on my 06 with 133000 on the od. It was the melted connector, seems like a definite defect judging from all the posts on this form.
 

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