Question about 2000 GMC Sierra

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Intermittent cooling from the air conditioning

When the air temperature outside is 100 degrees f. or higher at times my a/c blows cool air instead of cold air. i checked the temperature of both lines going to the evaporator at the firewall and they are appx. 34 degrees f. also once this weekend the blower motor delayed coming on for 2-3 seconds. the a/c works normally when the outside air temp is 90 degrees or lower. I'm thinking it's possibly the a/c control panel in the dash not sending the correct information to a blend door motor or a bad blend door motor or both. have you seen this before?

Posted by Anonymous on

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  • GMC Master
  • 540 Answers

If you want a quick check of the blend door system,clamp off the heater hoses,as you would if you were changing a heater core and drive as you would.Do not disconnect them,just clamp them.
Also,don't over look air flow through the a/c condenser at the front,any restriction of air flow or a slow fan or only one running of 2 when 2 are needed?

Posted on Apr 30, 2017

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Posted on Jan 02, 2017

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  • 1 Answer

SOURCE: Yukon A/C, rear blows cold, front ducts a LOT warmer.

There is only one A/C system split into 2 zones. Check the blend door actuator, it may have failed in one position or something may be jamming it. Also check the control panel in the dash, My 98 yukon did the same thing, no matter what temp you selected for the front it would blow at about 70 degrees. There is a circuit board in the control panel that gets corroded and one of the circuits controls blend door operations. Have a look.

Posted on Jun 12, 2008

JMMARRERO59
  • 77 Answers

SOURCE: 1998 Dodge Durango no heat when using heater.

BLEND DOOR STUCK OR BROKEN. NEEDS TO REMOVE DASH AND HEATER/EVAP CORE BOS TO REPAIR REPLACE.

Posted on Jan 08, 2009

  • 20 Answers

SOURCE: Climate control air conditioner stops working due to incorrect ambient air temperature

Same car, same problem. Press MODE, FRONT and REAR buttons together to reset tempreture. You probably need to replace the sensor GM part number 15047946 it is in the front grill email me for a picture. chris.abbott@gmx.com

Posted on Jun 28, 2009

matney68
  • 426 Answers

SOURCE: my climate control starts blowing hot air while a/c is on

Make sure you have fully charged AC sytem first, if so Im sorry to tell you this but this is a difficult deal.you may not be able to correct this without taking it to a repair shop with gm scan tool. Reason being the actuators for the hvac that most likely are malfunctioning from either them or another component being bad , require recalibration.The other reason would be the body control module related.It would have to be scanned for U codes which can effect the hvac control.Sorry but thats what I know.

Posted on Sep 06, 2009

Testimonial: "Tahnk you for your prompt reply. That is about what I figured I was gonna hear, on to the shop I guess."

  • 1 Answer

SOURCE: Air conditioner blows hot air after 30 seconds on

I have had this problem. I am not a mechanic...so to correct the issue temporarily, I simply turn off the car and restart. This has worked everytime for me. In extreme cases, I think you can also remove the AC fuse and start the car, which will also reset the computer. I also think that by taking the climate control off the "AUTO" setting has worked in the past.

Posted on Oct 27, 2009

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1 Answer

What happen when air condidtion is blowing just cool air


What temperature have you set the inside temperature to be?? Must be warmer than the outside temperature.
Could be a blocked heater hose ... can not help where to look or find.

Jun 21, 2014 | 2004 Nissan Maxima

Tip

Tips for operating Air conditioning system on Toyota Hilux and someother...


To cool off your Toyota after it has been parked in the hot sun, drive with the windows open for a few minutes. This vents the hot air, allowing the air conditioning to cool the interior more quickly.

Make sure the air intake grilles in front of the windshield are not blocked (by leaves or snow, for example).

On humid, do not blow cold air on the windshield. The windshield could fog up because of the difference in air temperature on the inside and outside of the windshield.

Keep the area under the front seats clear to allow air to circulate throughout the vehicle.

On cold days, set the fan speed to high for a minute to help clear the intake ducts of snow or moisture. This can reduce the amount of fogging on the windows.

When driving on dusty roads, close all windows. If dust thrown up b the vehicle is still drawn into the vehicle after closing the windows, it is recommended that the in intake be set to FRESH and the fan speed to any setting except "OFF".

If following another vehicle on a dusty road, or driving in windy and dusty conditions, it is recommended that the air intake be temporarily set to RECIRCULATE, which will close off the outside passage and prevent outside air and dust from entering the vehicle interior.

HEATING

For best results, set controls to;
Fan speed ---- Any setting except "OFF"
Temperature----Towards WARM (red zone)
Air intake ---- FRESH (outside air)
Air flow ---- FLOOR
Air conditioning ---- OFF

For quick heating, select recirculated air for a few minutes. To keep the windows from fogging, select fresh after the vehicle has been warmed.

Press the "A/C" button on for dehumidified heating.

Choose floor/windshield air flow to heat the voltage interior while defrosting or defogging the windshield.

AIR CONDITIONING

For best results, set controls to;

Fan speed --- Any setting except 'OFF"
Temperature --- Towards COLD (blue zone)
Air intake --- (outside air)
Air flow --- PANEL
Air conditioning --- ON

For quick cooling, move the air intake selector to recirculate for a few minutes.

VENTILATION

For best results, set controls to;

Fan speed --- Any setting except 'OFF"
Temperature --- Towards COLD (blue zone)
Air intake --- (outside air)
Air flow --- PANEL
Air conditioning --- ON

DEFOGGING

The inside of the windshield

For best results, set controls to:

Fan speed --- Any setting except 'OFF"
Temperature --- Towards WARM (red zone) to heat; COLD (blue zone) to cool
Air intake --- FRESH (outside air)
Air flow --- WINDSHIELD
Air conditioning --- ON

The outside of the windshield

For best results, set controls to:

Fan speed --- Any setting except 'OFF"
Temperature --- Towards WARM (red zone)
Air intake --- FRESH (outside air)
Air flow --- WINDSHIELD
Air conditioning --- OFF

On humid days, do not blow cold air on the windshield. The windshield could fog up because of the difference in air temperature on the inside and outside of the windshield.

DEFROSTING

The outside of the windshield

For best results, set controls to:

Fan speed --- Any setting except 'OFF"
Temperature --- Towards WARM (red zone)
Air intake --- FRESH (outside air)
Air flow --- WINDSHIELD
Air conditioning --- OFF

To heat the vehicle interior while defrosting the windshield, choose floor/windshield air flow.

on Feb 14, 2011 | Toyota Pickup Cars & Trucks

1 Answer

1994 Chrysler Lebaron Convertible In traffic with


If the cooling system is functional, yes.
The ac condenser adds heat to the air coming thru the radiator when the ac is on. If the engine cooling system is weak, the extra heat will make the engine run hot.
Low coolant flow thru the radiator is a common cause.

Sep 01, 2013 | 1994 Chrysler LeBaron

1 Answer

My xj runs well at speed, but when idling in traffic, the idle speed races and the engine temperature rises.


Check your cooling system - ESPECIALLY if you are driving a 4.0 L6...
Your engine's life is in the cooling system. If this engine overheats, you will crack the head or worst.
I would suggest (if you are mechanically inclined) that you check your coolant level - if you have added any recently, you have a problem.
Check the radiator for leaks, rusty spots, etc. I would also suggest that you open the draincock for the radiator (with a hose attached) and check the condition of the coolant. IF nothing comes out or anything other than green coolant comes out - you will need to flush the cooling system, and replace the coolant.
Now, it if was mine...(I own a 1993 ZJ, and previously owned a 1990 XJ)
I would purchase a new radiator - I bought my last one at 1-800 Radiator for the ZJ - it was $130 dollars with tax. New 192 degree Thermostat from NAPA or other reputable parts house. And the $4 thermostat gasket from the Jeep Dealer. The gasket is Daimler-Benz designed, and prevents galvanic corrosion (aka "my thermostat house was eaten by zombies"). This is the only gasket available that prevents this, and is worth the trip to the dealer.
Disconnect the battery, flush the cooling system, and drain. Replace the radiator with your new one, remove the thermostat housing, CLEAN everything and blow out with air, replace thermostat, Check all your hoses (inside of hose, more than the outside), and replace as needed. I would probably replace all of them at this point, but...
Refill with 50/50 Coolant/Distilled Water, and you should be good.
Now, what the H*^& does the idle have to do with speed racing and engine temp???
Jeeps, especially in the past twenty years, have used lower fuel/higher air ratios to reach fuel economy and emission goals. These cause higher engine temperature. IF the cooling system is great, not a problem. But if a problem exist with the cooling system, all that extra heat causes higher idle (due to premature ignition of fuel/air) and higher temperature (due to lack of cooling ability).
Hope this helps...

Nov 19, 2011 | 1989 Jeep Cherokee

1 Answer

1998 gmc surburban. front blows 82 degrees, rear blows 48 degrees. ambient is 91 degrees. this is with max-recirc-full tilt.the valve for the heater core does not change position no matter where i put the...


Hi John,
Your right with your diagnostics, you have a blend door problem. If your switching to cool air and it is still hot then you also have a heat exchange unit fault, this is the component that changes the water flow from hot to cool by shutting off. If it is not operating correctly this will give you constant hot air no matter where you temperature switch is positioned.
As for the warm air while the engine is cold, sounds like the blend door is still open to atmosphere tempreture and if it is hot outside will pull that hot air into the inside of the vehicle.
Have the heat exchange valve checked, and the only way the check blend door operation is to remove the wiring from the blend doors and have the circuit tested. If the circuit is ok then the blend doors will need to be replaced.
Hope this helps

Jul 24, 2011 | 1998 GMC Suburban

2 Answers

Air Conditioner stops blowing cold air when vehicle is not moving


plus one on the cooling fan problem. if it was low on charge then as you slow down, condensor temps and line prressures would raise therefore it would cool at low speed and and not when moving since the incoming air would drop system temp,reducing line pressure and then cusing compressor to cycle. the auxillary cooling fans must be on whenever a/c is on, if not, thats your problem. get this taken care of because if you get stuck in traffic, your engine will overheat also if fans are not running

Sep 02, 2009 | 2007 Ford Five Hundred Limited Sedan

1 Answer

My car 2005 Nissan Altima has been overheating when its 95-100+ degrees outside and when the needle hit the end of the icon on the dashboard the air condition starts to just blow normal air. After the car...


first useing a scanner or temp gun check the actual engine temp. if it is hot check for fan opperation, air lock in the cooling system water pump operation I think youll find the prblem to be the fan

Aug 18, 2009 | Nissan Altima Cars & Trucks

1 Answer

I have a 2000 Mirage and i the morning my a/c works it cools but in the afternoon when i leve my work it blows out hot air can you help please. Les


It sounds like your air conditioning is actually not the issue here. If your a/c is working in the morning, there is no reason it shouldn't work at a different time of day. What most people don't realize is how hard an a/c system must work to cool off a car that has been sitting in the sun all day during a hot summer. Even if you leave your windows down to avoid the greenhouse effect (which can make a HUGE difference if you don't) the interior of your vehicle is still probably a dozen or more degrees hotter than the temperature outside. This is because only so much air can circulate through cracked windows, and because of the direct sunlight shining onto your vehicle's interior and upholstery. Even once the a/c system is up and cooling the air inside your car, it is still struggling against the heat stored in your car's interior, which is giving up its heat to the surrounding air as it cools off. This can take quite awhile, and if your drive home is a short one, the a/c system may never have time to fully compensate once the car's interior has cooled to match the interior's temperature. To make matters worse, if your drive home is one through the city, you can expect your a/c to suffer. The air conditioning system needs good, steady airflow over it's condenser (a radiator-type part located just behind the front grill) and lots of starts and stops in a city or heavy traffic area can obviously prevent this. Above all though, the most important thing to remember is that with even a perfectly functioning a/c system, you can usually only expect about a 30 degree drop on average from the outside air temperature. So, if it is 100 degrees out, depending on the ambient pressure and humidity (also things which can affect an a/c system's efficency) you may only get air that's 70 degrees out of your vents. I would recommend always rolling your windows down half an inch or so, and park in the shade whenever possible. Also, putting a sunshade in your front (and sometimes even rear) windows, and having your side windows tinted (when legal) can go a LONG way toward keeping your interior as cool as possible when sitting parked in the sun for long periods of time

Jul 10, 2009 | 2000 Mitsubishi Mirage

1 Answer

We live in Austin, TX where the temperatures can reach 100-105 degrees during the summer. My 2007 CLK550 Cabriolet A/C will not adequately cool the car. We have returned the vehicle to the dealer several...


i recommend tinting your windows,this will help a lot!also,make sure that they have all the coding in the aac control unit correct,make sure the have it set to hot countries,100 percent
recirculated air possible and that theres no positive temperature adjustment(ie-could be coded to blow a few degrees warmer than you,the customer,actually sets it)
jess

Jul 29, 2008 | 2006 Mercedes-Benz CLK 500

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