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The driver side blows heat but the passenger side blows cold air

Tiny
JOHN9878
  • MEMBER
  • 2012 CHEVROLET TAHOE
  • 3.6L
  • V8
  • 2WD
  • AUTOMATIC
  • 86,000 MILES
When I turn the heat on, the driver side blows heat but the passenger side blows cold air. I don't hear any unusual noises.
Wednesday, October 23rd, 2019 AT 10:11 AM

36 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,747 POSTS
Welcome to 2CarPros.

On this vehicle's dual climate control, there are two blend air door actuators. Most likely, the one for the passenger side has failed.

Take a look through this link:

https://www.2carpros.com/articles/replace-blend-door-motor

Now, I attached the pics specific to your vehicle for right side actuator replacement. Pic 1 shows location and pic 2 are the directions.

What I would suggest is to locate and test the switch to see if it is getting power. If there is power and the actuator isn't responding, replace it.

Here are a few links you may find helpful:

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

https://www.2carpros.com/articles/how-to-use-a-voltmeter

https://www.2carpros.com/articles/how-to-check-wiring

_____________________

Let me know if this helps or if you have other questions.
Take care,
Joe
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Wednesday, October 23rd, 2019 AT 8:24 PM
Tiny
MIAMISAMMIE
  • MEMBER
  • 1 POST
  • 2006 CHEVROLET TAHOE
  • 235,000 MILES
All the controls work and lights are working on dash for temperature, but no heat is blowing on any fan settings.
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Friday, February 19th, 2021 AT 7:50 PM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Try pulling HVAC fuse inside truck it will reset the actuators. Your blend door actuator is the problem if both heater hoses are hot when truck warm. If it does not blow heat after a reset then check to see if actuator is getting power or not. You may have two actuators one for left and one right. See pictures. Dash has to be pulled in order to replace one of them.
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Friday, February 19th, 2021 AT 7:50 PM (Merged)
Tiny
CASEYSAMSON
  • MEMBER
  • 1 POST
  • 2006 CHEVROLET TAHOE
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 67,000 MILES
I added some coolant because and the level is still low. Do you keep putting coolant in or do you add water?
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Friday, February 19th, 2021 AT 7:50 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,747 POSTS
Coolant needs to be mixed at a 50% coolant and 50% water. If the coolant level is too low, you won't get heat.

This guide can help as well

https://www.2carpros.com/articles/car-heater-not-working

Let me know if you have other questions.

Joe

PS: Mix the water and coolant prior to putting it in because if you only add water and allow the vehicle to sit, it will freeze. If you already only added coolant, don't worry. Just do it from this point.
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Friday, February 19th, 2021 AT 7:50 PM (Merged)
Tiny
VICTOR72RAMIREZ
  • MEMBER
  • 1 POST
  • 2004 CHEVROLET TAHOE
  • V8
  • 2WD
  • AUTOMATIC
  • 84,000 MILES
Turn the heater on. It either doesn't work at all just blows air not heated. Or one side or the other will work. Sometimes when the air conditioner is on the heater will blow? Today the engine coolant light came on and said it was overheating. Do you think this could all be the same problem?
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Friday, February 19th, 2021 AT 7:50 PM (Merged)
Tiny
BARBEE00
  • MEMBER
  • 1 POST
Hello,

Yes the low engine coolant will cause the heater to act strangely. Here are two guides to help us see whats going on with the heater and coolant leak.

https://www.2carpros.com/articles/car-heater-not-working

and

https://www.2carpros.com/articles/car-is-leaking-coolant

Please run down these guides and report back.
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Friday, February 19th, 2021 AT 7:50 PM (Merged)
Tiny
ALLEN13
  • MEMBER
  • 1 POST
  • 2004 CHEVROLET TAHOE
  • 5.3L
  • V8
  • 2WD
  • AUTOMATIC
  • 200,000 MILES
I just replaced the thermostat, water pump, temperature sensor, and the radiator. It was running fine when I just had water in the system, but after flushing water out of entire system and replacing it with the coolant the vehicle began to overheat again? What's the next step?
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Friday, February 19th, 2021 AT 7:52 PM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good evening,

Did you bleed the system?

I would start by removing the radiator cap and run the engine at 1,200 rpm. Have someone watch the coolant level and add as needed. Do this until you start to get heat and then make sure the coolant is topped off and not leaking.

Then take it for a ride and make sure the heater still works.

Roy
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Friday, February 19th, 2021 AT 7:52 PM (Merged)
Tiny
SCHOOLMAN
  • MEMBER
  • 3 POSTS
  • 2003 CHEVROLET TAHOE
  • V8
  • 4WD
  • AUTOMATIC
  • 120,000 MILES
Hey guys.I have a 2003 Chev Tahoe with cabin AC/heat. Seems the system works for AC, but when the overhead temp **** is on heat I only get cold air blowing. Is there a temp related item I can replace?
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Friday, February 19th, 2021 AT 7:52 PM (Merged)
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
Feel the heater hoses, they BOTH need to be hot, if only one is hot, the heater core is clogged, if both are hot, the temperature blend door inside the plenum(box) is stuck, either from rust on the shaft, or a bad actuator. If both hoses are cold, check your thermostat. If both are hot, have the truck scanned for codes, this will reveal a bad control panel or door actuator.
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Friday, February 19th, 2021 AT 7:52 PM (Merged)
Tiny
SCHOOLMAN
  • MEMBER
  • 3 POSTS
The heat in the front of the truck works great. Is the heat system a different system?
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Friday, February 19th, 2021 AT 7:52 PM (Merged)
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
Yes, if it's the rear unit, the same rules apply back there, plus a check of the heat system via a scan tool capable of reading "B" codes. This will pinpoint the problem part. This is a complex system, and without a scan, you will be just guessing at what part needs replacement. Checking the hoses is too see if the mechanical portion of your system is working, but it also has many electronic sensors and actuators to perform the work. Is yours an auto temp or manual system?
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Friday, February 19th, 2021 AT 7:52 PM (Merged)
Tiny
SCHOOLMAN
  • MEMBER
  • 3 POSTS
There are three ****s ceiling mounted above the rearview mirror that control the rear cabin only. **** For fan control with auto/ manual setting, temp and vent location The main system on dashboard is auto for front passengers only?
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Friday, February 19th, 2021 AT 7:52 PM (Merged)
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
Ok sounds like auto system, here's a diagram of the parts and location, I do recommend a scan!
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Friday, February 19th, 2021 AT 7:52 PM (Merged)
Tiny
WILLIAM HANNA2
  • MEMBER
  • 1 POST
  • 2003 CHEVROLET TAHOE
  • 5.3L
  • V8
  • 2WD
  • AUTOMATIC
  • 225 MILES
One day heat and A/C worked fine then the next few days heat went out then the A/C went out. I have no heat only cold air now.
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Friday, February 19th, 2021 AT 7:52 PM (Merged)
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good morning,

Did you check the coolant level?

https://www.2carpros.com/articles/radiator-pressure-test

A thermostat will cause a no heat condition.

https://www.2carpros.com/articles/replace-thermostat

Has the car overheated?

A blend door actuator could also cause this issue.

Roy
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Friday, February 19th, 2021 AT 7:52 PM (Merged)
Tiny
SHILLARD31
  • MEMBER
  • 3 POSTS
  • 2001 CHEVROLET TAHOE
  • V8
  • AWD
  • AUTOMATIC
  • 125,567 MILES
My heater is not getting hot the heater cord has been checked, the radiator has been flushed, the hose has been checked and what else is there to be done. Please help
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Friday, February 19th, 2021 AT 7:53 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,747 POSTS
Is the heater hoses both hot? Here is a guide to help you.

https://www.2carpros.com/articles/car-heater-not-working

Joe
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Friday, February 19th, 2021 AT 7:53 PM (Merged)
Tiny
SHILLARD31
  • MEMBER
  • 3 POSTS
Checked to see if the floor on the passenger side was wet but it was not.
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Friday, February 19th, 2021 AT 7:53 PM (Merged)

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