No air from vents

Tiny
MIDNITETIGER2
  • MEMBER
  • 2001 BUICK PARK AVENUE
  • 100,000 MILES
My car was blowing air only from defrost for a couple months, no big deal. Yesterday, it started blowing only from the vents no matter what and I could not defrost my windshield. At first I believed it to be a mode door actuator, but I do not think this car is equipped with one? Could it be a vacuum hose issue? Also, I noticed the heater would not come on ever unless I first turned unit off, then back on again.I removed all HVAC fuses, waited five minutes, reinserted fuses, turned on car electric only, heard heater "re-calibrating", but same thing, air from vents only now.
Friday, March 2nd, 2018 AT 5:02 PM

6 Replies

Tiny
MIKE H R
  • MECHANIC
  • 3,094 POSTS
Just about all cars have a somewhat a door. Check under the dash to see if you can hear any hissing sounds. If possible move the vacuum hoses around while changing the heater control from floor to defrost. If you find that there is a leak, you might fix it if there is enough extra hose to remove the break and reattach the hose.
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Saturday, March 3rd, 2018 AT 6:56 AM
Tiny
MIDNITETIGER2
  • MEMBER
  • 4 POSTS
Thanks, Ritzel.I'm giving it a look now. Trying to locate the hoses under the hood also for leaks. Then, I'll check under dash/behind glove box.
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Saturday, March 3rd, 2018 AT 11:06 AM
Tiny
MIKE H R
  • MECHANIC
  • 3,094 POSTS
You are welcome.
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Saturday, March 3rd, 2018 AT 6:10 PM
Tiny
MIDNITETIGER2
  • MEMBER
  • 4 POSTS
I did not see any broken or disconnected hoses. Getting pretty good vacuum up behind the glove box at the pump/motor (?). When I do remove all HVAC fuses, then reinstall them and let unit "re-calibrate", I can see up under the dash/behind the glove box a big white panel swing horizontally, telling me the actuators are working okay. I think. I may go to the junk yard tomorrow and get a new control unit and possibly the programmer if I can locate where they are. I am hoping to get both for under $80.00. What I think may be my mode door actuator is so far up inside behind the glove box I can barely even see it with glove box pulled out and the bottom panel removed, let alone even touch it.
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+1
Saturday, March 3rd, 2018 AT 7:44 PM
Tiny
MIDNITETIGER2
  • MEMBER
  • 4 POSTS
Got an AC programmer and the control unit from the junk yard today, same symptom. Took them back, and pulled a mode door actuator which was impossible to get at. I had to rip most of the dash out, cut all the wires going to the fuse box, rip that out of the way, and I was still barely able to get my hands on the mode door, let alone get a socket on it. I have no idea how I am going to pull the one out of my car. There has to be a better way to get at it. If I could only pull the airbag compartment or come in from the firewall, but I think that is impossible. Ugh. :-(
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Sunday, March 4th, 2018 AT 2:21 PM
Tiny
STEVE W.
  • MECHANIC
  • 13,576 POSTS
The only way to reach and remove the mode actuator on that car is to remove the dash assembly. The mode actuator itself is behind the blend actuator for the drivers side. The blend actuator moves a large cam that has to be timed during assembly. The mode unit is under that cam. Yep, they are a pain to get into.
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Tuesday, March 6th, 2018 AT 12:13 PM

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