Sonoma/S10 heater blend door

Old 02-02-08, 01:33 PM
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Sonoma/S10 heater blend door

I no longer have feeling in my feet. My heater (2002 Sonoma) works fine except the knob setting to the lower foot area seems to not divert warm air to your feet. In fact its disgustingly COLD. My legs and feet turn numb on a 20 minute ride to work. There is lots of hot air, you just can not get any flow to the foot area.

I had this problem a few years ago that I diagnosed as the door inside the duct to have broken at the axle/shaft: where it connects to the actuator cable up under the dash. The actuator is pneumatic and it worked well, just moving only the broken small diameter plastic shaft.

It was reparied under warranty (Over $400 charge to replace a junky-cheap plastic part that costs a few bucks)

My question is does any body know what is involved with the repair ? It sure seems like you need to disassemble half the dash to get at the duct work. Secondly, I dont want to put the same doomed-to-fail part back in there. I am likely to keep the truck for a while and I want only to fix this once. I am thinking once I get it apart I will figure out a way to reinforce the break point but maybe someone has already soved the problem ?

Old 02-02-08, 02:00 PM
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I had the same thing happen to my Chevy Malibu but mine controlled the OUTSIDE AIR / MAX AIR door and yes you have to remove half the dash to get to it but I saw what was involved and got creative.

I simply drilled a small hole in the back of my glove box and ran a thin rod ( straightened out coat hanger) through the hole and made it attach the blend door and put a loop or handle on the other end inside the glove box and it has worked great for the last 5 years.
If I need OUTSIDE AIR or MAX AIR I just open the glove box and push or pull the rod.
It beats paying $400.00 bucks for the same junky piece of plastic that WILL break again.
And we wonder why Detroit is losing to imports...........
Old 02-04-08, 04:32 PM
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Sonoma heater door

I like everything you said, only because the shaft is broken off I can't get at the door. Earlier, I tried poking around up the duct outlet with a stuff wire and I couldn't get at anything that felt like the door.

I have no clue how the door inside the duct is oriented or even exactly where its located: only where the now broken junk plastic shaft used to go into the duct.

Maybe I will search the internet for some sort of schematic or get a shop manual to see how this thing goes together.

I recall my youth when I could check a shop manual out of the public library. But, that's when there were only about 6 or 7 makes of cars. Oh well, any further input from anyone is appreciated.
Old 07-19-08, 06:10 PM
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blend door problems

I have a 93 s10 and a/c works great if i am sitting still or at cruising speed, (light load). When I accelerate, the air volume goes down which means to me that the blend door is closing off. I have checked for vacuum leaks and found none so I suspect that the blend door actuator is sticking or something along that line. I was told by an old mech. that it could be reached through the glove box door although not easily. Any
one have a solution?
Old 07-21-08, 08:24 PM
Join Date: May 2008
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your HVAC system is controlled by engine vacuum.

google Blazer Forum and search for 4x4 no worky. Yes the same vacuum system that controls your 4x4 system also controls your HVAC system. and it controls engine preformance.

Which engine do you have?

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