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Chevrolet Blazer Heating Ventilation and Air Conditioning

118 messages,  Last post on Nov 01, 2009 at 9:53 AM

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What is this discussion about? Chevrolet, Heating / Cooling, SUV


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#106 of 118
98 Blazer A/C problem by cach22
May 12, 2009 (2:56 pm)
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'98 Blazer LS
4 door
4WD
130,000+ miles
I do NOT have automatic temperature control.
The A/C blows only hot air. The vents DO get warmer if I turn the temp dial to heat. I do not hear the compressor clutch engaging nor do I see/hear the accompanying load increase on the engine. I have checked the low side pressure and it actually reads high (in the red on the cheapo gauge that comes with the cheapo recharge kit).
 
How do you check the compressor to see if it is bad or not?
Or, is there something else that may be causing this?
 
I replaced most of the A/C system a couple of years ago with the help of a mechanic friend. The compressor shelled and contaminated the system with bits of metal. We flushed, replaced parts and had the whole thing working great. About 3 months later I parked it... for about nine months. It was when I started driving it again that the A/C no longer worked.
#107 of 118
Re: 98 Blazer A/C problem [cach22] by dfhltd
May 12, 2009 (4:05 pm)
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Replying to: cach22 (May 12, 2009 2:56 pm)

First check the compressor is not frozen by seeing if you can turn the shaftthat engages the clutch. If you can't get leverage to do that then heres another idea. There is a wire that goes to the clutch. Disconnect that and supply 12 volts directly to the compressor clutch to see if it engages and the compressor will turn. Don't let it run very long! Just long enough to prove the compressor is turning.
 
Assuming that it will turn then the problem lies elsewhere. The wire you disconnected is the signal to engage the clutch and the electricity isn't getting through. This is because there are a couple of safety sensors checking for pressures in range. The fact that the low side is out of range indicates the low side sensor is not allowing the signal through. The high side may have a sensor too. In any event these are safety devices to prevent the compressor frombuilding up too much pressure and exploding the pipes and connectors. This is what happens when air gets in the system. The compresor will keep compressing the air until something bursts. Normally the coolant will be compressed from a gas to a liquid and pressure will remain normal. But you probably have lots of air in the system. Coolant leaks out generally through the seals where the hoses connect to the compressor and dryer etc. They have little O rings and special seals which may have cracks or are installed incorrectly. I got some seals from the auto part store that looked right but wern't. this part is really tricky and could be your problem. Anyway you have to get all the air out of the system before you recharge. You can't just add more coolant. That won't work. Then when you get it running again there is a test that can detect leaks which you should do around any thing that has seals in it. Good Luck
 
Doug
#108 of 118
Re: 98 Blazer A/C problem [dfhltd] by cach22
May 13, 2009 (2:49 pm)
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Replying to: dfhltd (May 12, 2009 4:05 pm)

Doug,
 
How easily should the shaft turn? I tried to turn it and it did not budge. I actually scraped some metal filings off trying to get it to spin. Do I remove the belt to try this? Or is it safe to say that it is frozen up? I priced a new compressor and I must say I am not looking forward to replacing this thing.
 
I have yet to try applying any voltage directly to it. I have to rig something up. Plus I need to wait until it stops raining.
 
Thanks,
 
Ken
#109 of 118
Re: 98 Blazer A/C problem [cach22] by dfhltd
May 13, 2009 (4:14 pm)
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Replying to: cach22 (May 13, 2009 2:49 pm)

Ken
It's frozen. It should turn pretty easy. The clutch drive plate is on the front and easy to get to. It's disengaged from the drive pully. Normally the electricity pulls the drive plate and pulley toghether. You don't need to remove anything.
 
As far as the compressor it ony two bolts on top holding it on. You can get them off in 2 minutes. Disconnect the hoses and take off the drive belt. You can drive it that way until the new parts arrive. The AC belt doesn't drive anything else I don't think. You can try again to turn the compressor but it sounds like its frozen.
 
When you charge the system you need to put quite a bit of ester oil in the new compressor. You can buy at the local auto store.Without it it's like running an engine w/o oil. It will seize.
 
You need to flush the drier and evaporator and condesser to get any metal filings out that may have come from the compressor when it siezed. Figure out which way the coolant flows in the system and then blow through the dryer, condenser and evap in the opposite direction. Use AC flush and clean that you can buy at the auto store too. I think I used a hose and funnel to get as much flush as I could and then an air compressor to blast it through. I don't know if this is the approved way but it worked.
 
I bought a new compressor with a new clutch online for $160 - $200. I assembeled evertything and took it into a automeotive AC shop and had the system evacuated and filled with coolant for about $85. They can check to see if the pressure is right and the seals arn't leaking as part of the service.
 
Doug
#110 of 118
98 Blazer a/c drip pan drain line by rjmac
Jun 05, 2009 (4:37 pm)
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I can't take the sloshing noise under the dash any more. Before it really gets hot and musty smelling I would like to blow the line out with air (did this on a minivan years ago, worked great). PROBLEM I can't locate this line. I now have the wheel liner out and still can't see it! Any one got advice. Last fall the local garage had it on their lift and they couldn't find it either.
#111 of 118
Re: 98 Blazer a/c drip pan drain line [rjmac] by dfhltd
Jun 06, 2009 (11:05 pm)
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Replying to: rjmac (Jun 05, 2009 4:37 pm)

I don't know if there even is a dripline but the sloshing doesn't have to do with that. If there is a drip line it has to be located under the evaporator which is bolted to the engine side of the firewall in the middle. I'm guessing there is a hole or something that lets condensation just drip out the bottom on the ground. The cover comes off so you could loook insdie and see if there is a hole in the bottom under the evaporator core. There may not even be a hole.
 
The sloshing noise probably is the heater. I noticed that the heater core is pretty high and the hoses leading to it are longer than they need to be so they arch up. If there is air inn the system it will goe to the highest spot which is the heater core and hoses. Re route the hosesso they are lower than the heater. Make them shorter if necessary. Then find a way to bleed the air out of the system. Once there is no air in the system the noise will go away.
#112 of 118
2000 Blazer with Auto Climate Control by phillip64
Jul 18, 2009 (2:43 pm)
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Issue: I have no heat regardless of temperature control setting with the exception of when I set to full clockwise, and then gets hot as heck. AC works all too well and will freeze you out of vehicle. Again no adjustment with temperature control just cold as heck unless I turn temperature control fully clockwise, then heat takes over and it gets too hot in vehicle. Just a slight adjustment counterclockwise and all bets are off, no heat. Vehicle is equipped with auto climate control, just does not seem to work. Any and all advice welcomed. Thanks
#113 of 118
heater/air control by johnwny
Sep 28, 2009 (8:16 am)
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My air and heater both work but in differant settings. Air only works on far right of dial and heater on only works on center settings. Air/heat only blows out dash at you and alittle at windshield no matter what the setting on the dial. All fan settings work fine. Is it just a bad dial? Any ideas on this? Thanks
#114 of 118
Re: heater/air control [johnwny] by jlflemmons
Sep 28, 2009 (8:41 am)
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Replying to: johnwny (Sep 28, 2009 8:16 am)

Check the vacuum lines running from the intake manifold over to a tee near the brake vacuum booster and on to the vacuum resevoir in the left front fender. Very common for these to rot and leak with age, and will cause the symptoms you have described.
 
Good luck
#115 of 118
2002 blazer heater problem.... by gunnysarge
Oct 14, 2009 (3:48 pm)
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Guys my WIFE'S 2002 blazer has no heat .. i pulled the return heater hose and NOTHING.. one side is hot and the other nothing( its a little wet but no running water)... ???? can I use a air line to maybe blow the core out??? or is it to late and i have to replace it......????

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