Heat and air

Tiny
CYNDY JOHNSON
  • MEMBER
  • 2006 CHEVROLET IMPALA
  • 100 MILES
No air coming out of instrument panel.
Monday, August 28th, 2017 AT 10:31 AM

5 Replies

Tiny
STEVE W.
  • MECHANIC
  • 12,958 POSTS
Which engine do you have and which heating system. The manual system with 3 dials (wood trim) or the automatic version (gray trim) with a temperature control for driver and passenger?
Does the temperature change and fan speed control work?
You just cannot switch from floor/dash/defrost correct?

If so it is likely the mode actuator that is bad.
Replacing it isn't real difficult.
You remove the glove box door, then the glove box inner panel.
Once those are out the actuator will be on the end of the HVAC box just to the left of the inner glove box you removed.
Remove the electrical connector and the two screws that hold the actuator in place.

Once the new unit is installed you will need to remove the HVAC fuse for at least a minute. Replace the fuse and turn the key on. Don't touch the HVAC controls during reset.
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Tuesday, August 29th, 2017 AT 8:43 PM
Tiny
CYNDY JOHNSON
  • MEMBER
  • 3 POSTS
Thank you Steve for responding. It is dual control but has wood trim. Temperature does change and the fan speed does work. It just doesn't blow out the dash vents. We replaced the Mode actuator and reset by disconnecting the battery. We do not know where HVAC fuse is. After doing it still does not work. Any other suggestions? Thank you for your time
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Wednesday, August 30th, 2017 AT 5:18 PM
Tiny
STEVE W.
  • MECHANIC
  • 12,958 POSTS
Yeah, I just used the trim to tell the pictures apart. HVAC fuse is the one circled. Disconnecting the battery usually doesn't work for the reset as it doesn't tell the module to clear it's settings.
I've also had a few stubborn ones that I needed to use the scan tool to make them work.

If pulling the fuse doesn't do it then it's possible the door itself is broken inside the box. That isn't a fun thing because the entire dash has to come out to get the HVAC case out.
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Wednesday, August 30th, 2017 AT 7:01 PM
Tiny
CYNDY JOHNSON
  • MEMBER
  • 3 POSTS
I am so sorry to keep bothering you but you're all we got. Found the fuse and reset. Now my husband tells me we have no heat at all ( apparently he didn't check it before) and air conditioning comes out the defrost only, no floor or vents. No matter where we set the dial all we have is air conditioning coming out the defrost only.
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Thursday, August 31st, 2017 AT 9:53 AM
Tiny
STEVE W.
  • MECHANIC
  • 12,958 POSTS
Not a bother at all. Now if you start asking about shampoos or the best pizza......

OK, no temperature control and no mode control suggests the control head itself is bad or is not getting the proper power.

Grab a test light and do the fuse tests the easy way,
https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Now go to the underhood fuse block and check the Display and Airbag/Display fuses.
I would check all the fuses as GM likes to pull power off other circuits as well, but then they don't tag those as being involved.

If the fuses check out then you would replace the control head. The trim around it just clips into the dash, then 2 screws and the connectors and it's out. If you have a center console it's a bit more work but not that hard. Just be sure to get the correct one to match yours.
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Thursday, August 31st, 2017 AT 12:56 PM

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