Heater not working

Tiny
DKVOGEL
  • MEMBER
  • 1999 CHEVROLET SILVERADO
  • V8
  • 2WD
  • AUTOMATIC
  • 242,000 MILES
1999 Chevy Silverado heater not working. Replaced the thermostat heat still not working.
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Sunday, December 5th, 2010 AT 11:21 PM

26 Replies

Tiny
RASMATAZ
  • MEMBER
Check the heater core if its clogged and air blend if its opening to the heat position
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Sunday, December 5th, 2010 AT 11:38 PM
Tiny
61STEVE
  • MEMBER
  • 1999 CHEVROLET SILVERADO
  • V8
  • 4WD
  • AUTOMATIC
  • 140,000 MILES
I have little or no heat. Its not the thermostat.
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Friday, April 19th, 2019 AT 2:16 PM (Merged)
Tiny
BMRFIXIT
  • EXPERT
Check heater hoses they should be hot both
if not isolate the heater core and flush it
if they hot check the blend door operation
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Friday, April 19th, 2019 AT 2:16 PM (Merged)
Tiny
GGWOLVERINE1
  • MEMBER
  • 1999 CHEVROLET SILVERADO
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 135,000 MILES
The problem that I have is when I have the heater or defroster on hot I get nothing but cool air. The hoses going to heater core are both hot. I m not a mechanic so any advice would be greatly appreciated. Thank you.G
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Friday, April 19th, 2019 AT 2:16 PM (Merged)
Tiny
BMRFIXIT
  • EXPERT
Most likely to be a blend door actuator issue. If the thermostat is opening properly and heater core not clogged-up -could be one of the following: Heater control valve, air mix/blend/mode/recirculation door problems, vacuum and actuators to include the HVAC control module
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Friday, April 19th, 2019 AT 2:16 PM (Merged)
Tiny
VVP45883
  • MEMBER
  • 1999 CHEVROLET SILVERADO
Heater problem
1999 Chevy Silverado Two Wheel Drive Automatic

Have replaced thermostat, still no heat is there a valve somewhere that need to be replaced?
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Friday, April 19th, 2019 AT 2:16 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • EXPERT
Hi:
If the truck has a heater control valve, it would be on one of the heater core hoses. However, I don't think it does. Let me know if you find one.

Joe
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Friday, April 19th, 2019 AT 2:16 PM (Merged)
Tiny
CNJHART
  • MEMBER
  • 1997 CHEVROLET SILVERADO
Heater problem V8 Four Wheel Drive Automatic 223000 miles

i replaced my t-stat and fan clutch and I still have no heat what should I do?
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Friday, April 19th, 2019 AT 2:16 PM (Merged)
Tiny
JDL
  • EXPERT
Hi, does the engine reach operating temp? Are the heater hoses hot? Maybe the heater core needs to be flushed?
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Friday, April 19th, 2019 AT 2:17 PM (Merged)
Tiny
ALASKADOC
  • MEMBER
Where do I check the heater hoses? If heater core needs flushing, where is the heater core in my 1994 Chevy Silverado z71?
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Friday, April 19th, 2019 AT 2:17 PM (Merged)
Tiny
KEN
  • ADMIN
Hey,

You check the heater hoses up by the fire wall with the engine warm. Check your coolant level engine cold. To me though it sounds like you have a temperature blend door actuator that is out which is common. Here is a guide to help us fix your truck which is one of my favorites vehicles btw.

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

and

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

Check out the diagram (Below)

Let us know what happens and please upload pictures or videos of the problem.

Cheers, Ken
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Friday, April 19th, 2019 AT 2:17 PM (Merged)
Tiny
TERRY DON
  • MEMBER
  • 1995 CHEVROLET SILVERADO
  • V8
  • 4WD
  • AUTOMATIC
  • 129,000 MILES
Heater will not get hot
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Friday, April 19th, 2019 AT 2:17 PM (Merged)
Tiny
RASMATAZ
  • MEMBER
Try replacing the thermostat and see what happens don't work could be coming from an air mix/blend/mode/recirc door problems to include vacuum and actuators and the HVAC control module
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Friday, April 19th, 2019 AT 2:17 PM (Merged)
Tiny
NOHEATDUDE
  • MEMBER
  • 1992 CHEVROLET SILVERADO
Electrical problem
1992 Chevy Silverado V8 Four Wheel Drive Automatic 150k miles

No Heat, display, blower. Everything worked fine then the other day the digital display for my heat went black. The unit was repaced still nothing, the unit lights up with the headlights turned on but no display. Checked the blower relay switches, still no heat. Whats your solution. Thanks
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Friday, April 19th, 2019 AT 2:17 PM (Merged)
Tiny
MASTERTECHTIM
  • MEMBER


http://www.2carpros.com/forum/automotive_pictures/139033_no_11.jpg

chec the powe and ignition wires for voltage and then let me know
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Friday, April 19th, 2019 AT 2:17 PM (Merged)
Tiny
MASTERTECHTIM
  • MEMBER
Red wire and orange wire. My reply was chopped up
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Friday, April 19th, 2019 AT 2:17 PM (Merged)
Tiny
DAN_MAN12
  • MEMBER
  • 1994 CHEVROLET SILVERADO
  • V8
  • FWD
  • AUTOMATIC
  • 140,000 MILES
My heater is not blowing hot air. The fuse is good and the fan is blowing as it should. I can deal with that part but I think there is a problem with the heater core. I think it may be pluged up. I blew air through it and lots of rust came out. I am just wondering if air could pass but it still be too pluged to let water flow properly. Can you tell me how to go about checking this out and fixing this?

The heater core was cloged! I flushed it out and it now blows plenty of hot air! Thanks anyway!
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Friday, April 19th, 2019 AT 2:17 PM (Merged)
Tiny
BLACKOP555
  • EXPERT
Glad to hear you have fixed it.

And yes air under pressure can go through very minute holes and show flow, but water wont as its not under that much pressure.
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Friday, April 19th, 2019 AT 2:17 PM (Merged)
Tiny
RAPAULSON
  • MEMBER
  • 1989 CHEVROLET SILVERADO
  • V8
  • 4WD
  • AUTOMATIC
  • 260,000 MILES
I have checked as the truck warms up, one hose first warms up then the other as the water goes through the core. The blend door operates to change from defrost, windshield, to the floor, heater, but with no heat. Is the blend door also the directional door? How to fix and gain access, even if I can get the door (baffle) to open manually to let the air to blow into the heater core, if that is the problem?
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Friday, April 19th, 2019 AT 2:17 PM (Merged)
Tiny
WRENCHTECH
  • MEMBER
The blend door and the mode door are 2 entirely different components.

If both hoses are hot to the touch, then you likely have a blend door problem.

You should be able to access it by removing the glove box.

https://www.2carpros.com/images/external/57432979.jpg.gif
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Friday, April 19th, 2019 AT 2:17 PM (Merged)

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