Blows cold out of the vents sometimes when the heater is on?

VANESSA SMITH

MEMBER
2004 BUICK RANIER
6 CYL
175,000 MILES

I just had a blower motor resistor with auto temperature control replaced.

Monday, November 28th, 2022 AT 12:32 PM

3 Replies

KEN L

MASTER CERTIFIED MECHANIC
42,949 POSTS

This can happen when the coolant level in the radiator is low. Here is a video to help you check the coolant and be sure the engine is cold before you check it.

https://youtu.be/GSE9skKnOgY

This guide can help as well:

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

Please go over these guides and report back.

SPONSORED LINKS

Was this

answer

helpful?

Yes

No

Monday, November 28th, 2022 AT 5:45 PM

VANESSA SMITH

MEMBER
2 POSTS

Heat does come out, then all of a sudden, the heat coming out of the vents turns cool while heat is still coming out of defrost. Then it will go back to hot air. There should not be any air coming out of vents because it's on defrost.

Was this

answer

helpful?

Yes

No

Tuesday, November 29th, 2022 AT 7:22 PM

KEN L

MASTER CERTIFIED MECHANIC
42,949 POSTS

If the coolant is full, then it sounds like you have a mode control actuator that is out. Here is the location so you can check it out and replace it to fix the problem. Check out the images (below). Please let us know what happens.

Images (Click to make bigger)