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Discussion Starter · #1 ·
ok so after searching the forums i thought i had got an idea on how to solve the problem.I took off the mode actuator so i could manualy direct the air to the vents but no luck i can only send the air to the floor vents or through the defrost vents.i can hear the air blowing behind the dash but it wont come thru the vents.am getting frustrated now.seems like when manualy turning without the actuater on i get about 90 degrees of rotaition is there something inside that could be binding?It is on a 2004 gmc envoy with electronic climate control if that helps.all this started after i got sandwiched between 2 cars.i got rearended and that forced me into a car in front of me.before that the heater and a\c worked fine after no air from top vents and the rear control is malfunctioning the one accesible from the back seats with the radio tuner in it.a nice exploded view of hvac system would be nice so i can see what could be binding.thanks
 

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2003 gmc envoy_slt
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:tiphat Welcome :tiphat . Have you taken the truck in for any other damage from the accident? Was there any other damage? That should be fixed by the insurance of the driver that rear-ended you.
 

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I had not dash vent issue as you. Pull the fuse to reset system however ended up replacing actuator and now I'm good now. When I was installing the flap rotation was not much. Stupid question - Dash vents actually open right??
It's only a door system - If you pushed a stiff wire thru the vent you should probable be able to detect it down at the flap which might help make on sense on the flap orientation.

God Luck
 

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Discussion Starter · #5 ·
thanks for the replies guys i have givin up on this...i guess i will save up the 800 to a 1000 dollars and have a dealer look at it.i mean with no actuator and manualy turning the flap i still get no air out of the top vents
 

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My front vents stopped working before too. They didn't work for about 2 months. Then I went on vacation for a week, and when I came back they were working again. I've also heard disconnecting the battery for a few minutes sometimes does the trick.
 

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Discussion Starter · #8 ·
holy crap I actually figured it out :thumbsup:lol.now i feel dumb:duh:...i pulled the wrong actuator off.when i pulled the correct one i was able to direct the air up to the vents finally.i havent had air come out of those vents since october.what a relief thank you to everyone that helped i really do appreciate it:hail:
 

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Discussion Starter · #10 ·
I seen that illustration in another thread but i must have just looked at the underside of my dash wrong.like i said it made me feel real dumb when i pulled the actual mode actuator off and could redirect the airflow seems how i spent a couple of days searching the net on how to fix a stuck door lol.thanks again and especially thanks to you roadie for the link of the exploded views.that would have been real handy when i was replacing my p/s pump lol:thx:thx
 

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Did I fail to post this pic in this thread? I've posted it in about all other actuator-related thread.

Would this pic apply to an 2005 Trailblazer and if so then where is this diagram located in relation to inside the vehicle? Am I correct in assuming it's under the dash? From other threads i've read that the dash vent actuator is located above the gas pedal and I would need to remove some panels to expose?? Would there be a part number for the floor/Dash vent actuator?

Thanks
Taz
 

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2002 gmc envoy_sle
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HVAC Control

OK. Thanks for the illustration. I just replaced the alternator on my 2002 SLE (184k miles) and suddenly the rear defrost and air acturtors are all inoperative. I'll try the disconnect the battery trick.

The fusx box labels are somewhat cryptic. Does anyone have the secret decoder ring for the fuse box?

Tom
 

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To recalibrate the HVAC controller, just pull the HVAC-B fuse for 30 seconds. Then put it back, turn the ignition to RUN but no need to start the engine, and listen (and don't touch ANY control) for 90 seconds as the actuators all go through their paces.

If this reset fails to get the actuators to work properly, try it 3-4 more times, then give up, run a search, and replace the dead one(s).

Pulling the battery forces a recalibration process, and due to a GM misdesign, some weak actuators can't survive the recalibration. They used too many interns that year without enough adult supervision, I think.
 
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