SPONSORED LINKS

Heater blows cold air part of the time

Tiny
ZENTGRAF
  • MEMBER
  • 2003 CHEVROLET SUBURBAN
  • 75,000 MILES
2003 chevy suburban heater intermediately working. Blower appears to be fine but blows cold air. Found info about the heater valve, seems to be the issue but I cannot find where the valve is located on the car. Thanks in advance for any help!"
Monday, November 14th, 2011 AT 4:06 AM

24 Replies

Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Hello,

This car does not have a heater control valve it sound like the temperature blend door actuator is not working which is common. Here are two guides to walk you through the problem and the location of the actors as well.

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

and

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

Please run down these guides and report back.
SPONSORED LINKS
Was this
answer
helpful?
Yes
No
Monday, November 14th, 2011 AT 4:35 AM
Tiny
OIDAVEY
  • MEMBER
  • 0 POST
Thanks for this post I had this problem and had to replace the actuator cost me $67.00 all fixed! I love this site
Was this
answer
helpful?
Yes
No
Tuesday, February 19th, 2019 AT 6:51 PM
Tiny
POVLICJ1
  • MEMBER
  • 1 POST
  • 2003 CHEVROLET SUBURBAN
  • V8
  • 2WD
  • MANUAL
  • 115,000 MILES
Anti freeze is leaking and heater is blowing cold air. What do you think the problem is and how much should it cost.

Thanks

jp
Was this
answer
helpful?
Yes
No
Tuesday, February 19th, 2019 AT 6:51 PM (Merged)
Tiny
DOCFIXIT
  • MECHANIC
  • 18,828 POSTS
Where is it leaking and what is engine temp?
Was this
answer
helpful?
Yes
No
Tuesday, February 19th, 2019 AT 6:51 PM (Merged)
Tiny
MRJAXX
  • MEMBER
  • 22 POSTS
  • 1999 CHEVROLET SUBURBAN
  • 5.7L
  • V8
  • AUTOMATIC
  • 189,000 MILES
I have been trying to get my heater to work with no luck. At the relay by the resistor I am getting twelve volts in, but then when I test at the resistor it is a low reading. When I turn the switch from low to high and only two of the modes work. Is this a bad relay or is it something else? Dash control and roof control will not work. If I bypass the relay and jump it to the motor it will work.
Your help is much appreciated. Thanks,
Todd
SPONSORED LINKS
Was this
answer
helpful?
Yes
No
Tuesday, February 19th, 2019 AT 6:51 PM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
When you turn the switch three of the resistors work that can be a bad resistor on high it runs through the relay to the blower the relay is under hood. Check the switch as I do not know how many speeds you have I am assuming four.
Was this
answer
helpful?
Yes
No
Tuesday, February 19th, 2019 AT 6:51 PM (Merged)
Tiny
MRJAXX
  • MEMBER
  • 22 POSTS
There is a relay right next to the resistor and I was checking the incoming power to the resistor straight out of the relay and got five volts. The heater switch has four settings and three different control panels in the vehicle and none work. I switched out the AC relay under the hood. I have current going to the relay in the dash compartment and if I jump that to the resistor the blower comes on. Also, I noticed that when I press on the AC button or recirculating bottom the lights so not come on could this be the problem if these controls do not have power?
Thanks, Todd
Was this
answer
helpful?
Yes
No
Tuesday, February 19th, 2019 AT 6:51 PM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
It could be the control head which has to be scanned by a mechanic and or the relay for the blower. if you have a like relay try replacing it with that and see if blower works. you can also use the link provided on how to test the relay. But it may be control head which if you replace it will need to be programmed to your vehicle by a mechanic.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit
Was this
answer
helpful?
Yes
No
Tuesday, February 19th, 2019 AT 6:51 PM (Merged)
Tiny
MRJAXX
  • MEMBER
  • 22 POSTS
There are three control heads in the vehicle and none of them work, but as I was saying I have only five volts coming out out the relay which is puzzling me. I thought if a relay was bad nothing would go through.
Was this
answer
helpful?
Yes
No
Tuesday, February 19th, 2019 AT 6:51 PM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
No, the control head may be supplying the five volts to activate it. And it is getting twelve on one side but not putting the twelve volts to blower. Red wire twelve volts, orange five, blue twelve, purple wire to blower. Other wire ground wire to blower will vary voltage depending on setting of speed. Black wire ground. Front control module supplies power to aux control.
Image (Click to make bigger)
Thumb
Was this
answer
helpful?
Yes
No
Tuesday, February 19th, 2019 AT 6:51 PM (Merged)
Tiny
MRJAXX
  • MEMBER
  • 22 POSTS
Okay, so should I be looking for a control head? But why will none of the other ones work? I am confused.
Was this
answer
helpful?
Yes
No
Tuesday, February 19th, 2019 AT 6:51 PM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Have a mechanic scan for codes as another control head will need to be programmed and you wont be able to do that. If this is auto temperature control then it really possible to be something else causing it.
SPONSORED LINKS
Was this
answer
helpful?
Yes
No
Tuesday, February 19th, 2019 AT 6:51 PM (Merged)
Tiny
MRJAXX
  • MEMBER
  • 22 POSTS
So you think it could be the relay that ties in just before the resistor?
Was this
answer
helpful?
Yes
No
Tuesday, February 19th, 2019 AT 6:51 PM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
No, I sent a link on how to test a relay, but until you scan for codes you wont know what it is.
Was this
answer
helpful?
Yes
No
Tuesday, February 19th, 2019 AT 6:51 PM (Merged)
Tiny
MRJAXX
  • MEMBER
  • 22 POSTS
  • 1998 CHEVROLET SUBURBAN
  • 190,000 MILES
Hello, my heater will not turn on. Dash control and controls for the rear are inoperable. I checked the fuses and all good and switched out the relay under the hood. The resistor looks good, but could that maybe be the reason why the fan will not come on at all. And, there looks to be another relay behind the glove box by the resistor, is this part of the fan too? What should I do here I am freezing every morning!
Thanks, Todd
Was this
answer
helpful?
Yes
No
Tuesday, February 19th, 2019 AT 6:52 PM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Check items in picture. The blower relay for aux is in under hood fuse box so check there and one in picture is under hood as well.
Images (Click to make bigger)
Thumb
Thumb
Was this
answer
helpful?
Yes
No
Tuesday, February 19th, 2019 AT 6:52 PM (Merged)
Tiny
PETERGDION
  • MEMBER
  • 1 POST
  • 2000 CHEVROLET SUBURBAN
  • V8
  • 4WD
  • AUTOMATIC
  • 156,000 MILES
I have no heat in the front unit but it has heat in the rear unit. Everything seems to be working fine. It blows air but will not get hot.
Was this
answer
helpful?
Yes
No
Tuesday, February 19th, 2019 AT 6:52 PM (Merged)
Tiny
DOCFIXIT
  • MECHANIC
  • 18,828 POSTS
Blend door p[roblem maybe actuator or HVAC controller
Was this
answer
helpful?
Yes
No
-1
Tuesday, February 19th, 2019 AT 6:52 PM (Merged)
Tiny
2CP-ARCHIVES
  • MEMBER
  • 4,540 POSTS
  • 2000 CHEVROLET SUBURBAN
  • 223,000 MILES
My heater is not blowing heat and temp is runnin bout 85 c
Was this
answer
helpful?
Yes
No
Tuesday, February 19th, 2019 AT 6:52 PM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Check to see if both heater hoses ar hot then check the accumaltor under dash for heat. Onemay not be working. Generic pic enclosed.
Image (Click to make bigger)
Thumb
Was this
answer
helpful?
Yes
No
Tuesday, February 19th, 2019 AT 6:52 PM (Merged)

Please login or register to post a reply.

Related Heater Not Working Content

Heater Not Working
VIDEO
Heater Not Working
Instructional repair video
Heater Not Working
GUIDE
Heater Not Working
Step 1 - A heater cannot operate unless the engine is full of coolant/antifreeze. If coolant level is low check the system for leaks.
VIEW MORE

Sponsored links