Hot/cold air does not work all the way in front?

Tiny
KMKELSO81
  • MEMBER
  • 1999 CHEVROLET VENTURE
  • 2WD
  • 129,000 MILES
Hot/cold air works in back but in front of works but doesn't blow like it should. It just barely blows air.
Saturday, November 12th, 2022 AT 4:45 PM

8 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,170 POSTS
Hi,

If the fan is operating properly, have you checked the cabin air filter to make sure it isn't clogged?

The cabin air filter is located behind the glove box. If you haven't checked or replaced it, do this first and let me know what you find.

I attached the directions below.

Take care,

Joe

See pics below.
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Saturday, November 12th, 2022 AT 10:43 PM
Tiny
KMKELSO81
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They do look like they need to be replaced. I took them out and it still didn't blow correctly. I'll get new filters.
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Monday, November 28th, 2022 AT 2:30 PM
Tiny
KMKELSO81
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They do look like they need to be replaced. I took them out and it still didn't blow correctly. I'll get new filters. I don't know if it's different but it's actually a van.
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Monday, November 28th, 2022 AT 2:32 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,170 POSTS
Hi,

When you checked the airflow with the filters out, did you have the cover over where the filter was removed from?

Let me know. Also, let me know if the airflow directions are working properly.

Take care,

Joe
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Monday, November 28th, 2022 AT 8:29 PM
Tiny
KMKELSO81
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  • 5 POSTS
No, the cover was shut.
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Monday, December 5th, 2022 AT 5:08 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,170 POSTS
Hi,

The next thing I suspect is the mode door actuator is likely not getting the airflow actuators fully in position. Are you able to change airflow directions normally?

I ask because the actuators are engine vacuum actuated rather than electric. If the vacuum supply is weak or nonexistent, the doors will not move correctly.

If you look behind the controller, you will see a purple vacuum hose. Make sure it is fully connected and not leaking. That is the supply hose from the engine. If it appears good, remove it and start the engine. Place your finger over the end to confirm there is a good vacuum supply.

I attached the vacuum schematic below. Try this and let me know what you find. Also, with the engine running, see if you notice any hissing which could indicate a leak and note anything that appears disconnected.

Take care,

Joe

See pic below.
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Tuesday, December 6th, 2022 AT 1:56 PM
Tiny
KMKELSO81
  • MEMBER
  • 5 POSTS
Is this the engine or under the passenger glove compartment?
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Friday, December 9th, 2022 AT 1:17 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,170 POSTS
Hi,

The pic above is of the controller in the vehicle. If you notice on the left side, it says the source. That goes to the engine intake manifold which is the source of the engine vacuum.

If you can locate the purple hose, disconnect it, and start the engine. Place your fingertip over the end of the hose to see if there is a strong vacuum being supplied.

Let me know.

Take care,

joe
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Friday, December 9th, 2022 AT 9:41 PM

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