Heater stays on low setting

Tiny
APRYLJANOVICH
  • MEMBER
  • 2000 PONTIAC GRAND PRIX
  • 20,000 MILES
Hi, My heater only stays on the low setting. You can feel heat if you put your hand on the vents and it does defrost very slowly but it's not enough to keep you warm at all. We changed the blower motor but apparently that did nothing. We were thinking maybe it's the switch where you turn the dial but I don't know. Any help you could give would be very much appreciated since winter is coming.
Sunday, September 16th, 2012 AT 7:23 AM

7 Replies

Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Is your HVAC Automatic or Manual?
Does the air flow or blower motor noise increase when setting is at maximum?
Does the A/C work correctly?
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Sunday, September 16th, 2012 AT 7:29 AM
Tiny
APRYLJANOVICH
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It's a manual. It just doesn't really blow any air. You can hear it turn on but can barely feel the warm air. The a/c is the same.
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Monday, September 17th, 2012 AT 3:42 AM
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Does the blower motor noise changes when speed setting is turned to maximum?
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Monday, September 17th, 2012 AT 4:40 AM
Tiny
APRYLJANOVICH
  • MEMBER
  • 4 POSTS
The blower motor doesn't make any noise on maximum with the heat or a/c. The only noise I heard is when I changed settings like feet or defrost or vents, it would make a small poof and that was it. Hope this helps. Thank you.
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Monday, September 17th, 2012 AT 5:24 AM
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
What I am trying to determine is if the various speed settings makes any differences, a fault with air flow volume or a venting system fault. The motor shoud be turning at different speed at the various settings and do you feel any difference to the air flow and blower motor speed (determined by the noise level).

If blower motor works correctly, you have a fault with the vent system and check to see if you have a cabin filter. If it is dirty, it can affect air volume.
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Monday, September 17th, 2012 AT 5:36 AM
Tiny
APRYLJANOVICH
  • MEMBER
  • 4 POSTS
There are no differences at various speed setting or any other settings at all. I can feel heat when I put my hand up to the vent but it doesn't blow out like it should be on the settings. The only time you can somewhat feel the heat is while driving like the air flow from the outside. We did buy a new blower motor already and it just does the same thing. Thank you.
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Monday, September 17th, 2012 AT 5:45 AM
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
I am still not sure if I understand the problem correctly.

I have the schematics for the system and if you have a DVOM or test light, we can perform some testings.

I would suspect a fault with the blower motor control module.
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Monday, September 17th, 2012 AT 6:00 AM

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