Hi, 1998 black w/black leather, 210k, rebuilt tranny and a great engine. Anyway, Seems, like there is always outside air...cold!! coming into the cabin, no matter what setting is on the heater control head. I saw the actuators on the passenger side working, what is open such that I can't stop cold air from coming into the cab??? Getting code b0408 and code b0416
THanks in advance for any help
Terry

 

I FIXED MY BLEND DOOR ACTUATOR MOTOR WooHoo!!! If you want to know how I did it or things I learned inthe process...other than the fact that my blood is red like everyone else..ouch...you can email me at tgresser@aol.com
Just was not willing to pay 250 bucks because I had a broken 5 cent part...It's the principle of the thing..

 

On my 98 Jimmy I had a similar problem. A local friendly mechanic set me up so here goes what works for me. Open and empty your glove box. Drop the box straight down by releasing the spring mounted stopper on the left side. This gives you access to the mixer door. The linkage was broken on my door, so the fix was:
Remove the actuator (it lifts up and hangs out of the way)
Custom bend a long(ish) spring to grab onto the mixer door and pull it back (to the right) and hang the spring on a convienient rod to hold the door in position.
Close your glove box.
Remove the spring when you don't want heat (Spring, Summer, & Fall) Reinstall the spring when heat is required (Winter).
It works for me for several years now.

 

Hey, thanks for the reply, your mixer door actuator/diaphragm thing..yeah..Can you explain the specific functions of that door. The motor I fixed was for the blend door, I thought it was called, which open and closes air from ..I thought the engine area cause when it was broken, I could not stop heat from pouring onto my feet unless I had everything off and air sent to upper vents and those closed ...and then there was still some hot air. ..Now that that door closes with the motor, that problem has mostly stopped, it all seems to work better on the auto settings that on manual fan and such...Anyway, I'd love to learn about the different doors and actuators and how they work if you know more than I do so far...which isn't too much, ...the one thing I can tell you is that getting the blend door actuator motor off is a &*&#*!king bear, just about impossible without taking off the entire dash, but I did it by going behind and up further past that item you are talking about

 

Actually, no, I can't. All I can say is that I couldn't get heat and when i went to my brother-in-law's service place, the mechanic knew about this. Apparently it happens on Jimmy's (I assume Blazers too) regularly. There are two fixes. Take the entire dash apart to replace the broken door part or fit the spring. The spring cost me a $20.00 tip to the mechanic. To replace the part was the best part of a day's labor / shop rate.

 

Thank you Calico.
I've got no a/c right now, need a compressor and etc, but I was happy to learn what you shared cause now I can at least cut off the damn heat that kept pouring into the cabin no matter what I did. I just unplugged the vacuum line so that the diaphragm let go and the door closes, like taking off your spring, and then I plugged the vacuum line so it isn't sucking air and essentially putting a hole in the vac system..This winter I think I'll actually have heat now that the blend door fix I did will keep the cold air from pouring into the cabin..
THnkas for the replies.
T

 

Got the compressor and kit from rock, having it put in next week, so then we'll see what else isn't right. I did find that someone used bailing wire to connect the arm of one of the vacuum actuators under the drivers side, but it does seem to be moving correctly. I also today did the "re=learn" thing for the computer HVAC system, again, have to wait til the ac is back in and functional to see what is not and how it's working...seems like I can tell all the doors are moving, but just not sure what combination of doors opening and closing make the specific functions from the dash instructions

Oh, and thanks again Calico, rather than do the spring fix you mentioned, I just unplugged the vacuum to that diaphragm and plugged it for the summer, and when I unplugged the vacuum line the door goes to that same position, take care,
T