1996 Limited: blender door issue (no heat) with auto air con

[grantgrabert]

Weird one:
Wasn't getting any heat through the vents, no matter what setting it was on.
Confirmed coolant valve was switching over, so ruled that out.
Took out the blender motor/servo/actuator and it seems to be rotating just fine.
Flipped the blender flap with my fingers a few times and it seems to be moving normal.
I put the actuator back in and then it worked fine. I didn't fix anything and now I'm getting heat on high temp setting and cold on "max a/c" setting.
Weird.
2 days later same issue again. No heat.
Any ideas on what is causing this issue?
I'm thankful the actuator is easy to access so hopefully it is the cause but prefer to not throw parts at an issue without confirming what parts are needed.
Thanks for any help!

 

[Turdle]

Allow engine to cool, then take off radiator cap to check coolant level.

 

[410Fortune]

My guess is the axle shaft is broken, they split down the middle and bits of plastic fall out. Your blend door actuator was able to grab some piece of the axle shaft and rotate the blend door flap once but not again, after you fiddled with it with your finger.
Using your cell phone camera try to get a picture of the top of the axle with the bled door actuator removed
You likely still have half a circle in there
Sometimes we can use a small finishing nail and heat it up, push it through the blend door motor stub and snip it off to length, if installed correctly the new little metal stub will allow the motor to grab the door to open and to close

Best to start with a picture so you can look down and see what’s going on

They all break in time, it’s just how badly determines what repair is needed

I have used the dorman Blend door replacement parts to fix many many of these
Start with the pic

 

[grantgrabert]

New item by Grant Grabert. New item by Grant Grabert

 

[grantgrabert]

 

[410Fortune]

Yep half an axle shaft

 

[grantgrabert]

Yep half an axle shaft

Sorry 410. I'm not fully understanding your info. Would you have a photo to explain your fix? What should the axle shaft look like?

 

[410Fortune]

This is a half square
That is is the end of the blend door axle shaft or blend door rod or whatever you want to call it. Half of it is missing. This is typical, the shafts splits in half and the motor no longer can open and close the door
The door is a flap attached to that broken rod

Dorman makes a new stronger blend door, basically you cut the bottom of the box open and carefully, in the correct location, then you can drop the broken door out and install the new dorman door. The hole you cut is then patched with tape/ glue / silicon / more tape

Sometimes the fix is easier, years ago I learned that by using a finishing nail and a lighter uou can heat up the nail and press it through the white plastic square on the actuator, if placed in the right spot it can now grab that half square and once again open and close the door…. Temporary fix but can buy time

The finishing nail is then cut to length so it lands here when the motor / actuator is re installed

The red line represents the new nail

I have fixed a couple of trucks this way, my old 96 the repair lasted the life of the truck. I actually installed the finishing nail while we were driving through Oregon in winter with no heat… we had heat in 20 minutes… the alternative would have been 12v hair dryer from Walmart to get us defrosted and home to Colorado
Back then dorman did not make a new blend door the only option was to remove the dash and repair with factory parts…

 

[grantgrabert]

Thanks for the explanation. What if I stuff the shaft with some 2 part epoxy putty then set the actuator in place and let it form? Please let me know your opinion. Appreciated.

 

[410Fortune]

You would end up Gluing the axle shaft to the box
It Must be able to rotate it is simply plastic on plastic

Also if it did work you would now never be able to remove the blend door or actuator!

Tough working with glue in that area! I’m sure it could work if you could get the glue in the exact right spot and avoid it contacting the housing or actuator body

First see if you can manually rotate the blend door… with your fingers or a tool see if you can rotate the door and if it mives freely

 

[c96drumm]

I fixed mine 10 - 15 years ago with a new blend door from NAPA. I cut out the bottom of the plenum and replaced the door, then replaced the plenum piece I cut out. IIRC, I used epoxy to secure the piece and duct tape to seal the gaps. Still working.
The hardest part is the bodily contortions required to get under there to work on it.

 

[410Fortune]

Yes, I have it down to a 20-30 minute job. I use a multi tool to cut open the box in just the right spot, leaving the bottom hinge in place. Then the old broken door is fished out the bottom and the new door installed
File the cut so no plastic is on the way of the “door swing”, test it a few times then button the box back up

 

[EB4X]

..........

 

[grantgrabert]

I was thinking a putty that would harden, not adhesive. something that would mold to the actuators shaft to fit in the blend door socket with no adhesion.

 

[410Fortune]

Finishing nail works perfectly just fyi
Mark the correct location on the square tip of the actuator square nipple (red line I drew)
Heat up nail and press it through the plastic
Cut it to length with snips so it fits down in the hole, does not hit the sides but is able to grab the axle and twist
Nail goes about 1/8” from the tip of the actuator nipple so it’s far enough down in the hole

Glue it in place with a small piece of hot glue or silicon
Install actuator and test

I have done this repair upside down in the passenger seat while we were driving
I have used it a few other times over the years to fix blend door axles that look EXACTLY like yours

Also since your limited has eatc make sure you do a self test and clear any codes

 

[grantgrabert]

Finishing nail works perfectly just fyi
Mark the correct location on the square tip of the actuator square nipple (red line I drew)
Heat up nail and press it through the plastic
Cut it to length with snips so it fits down in the hole, does not hit the sides but is able to grab the axle and twist
Nail goes about 1/8” from the tip of the actuator nipple so it’s far enough down in the hole

Glue it in place with a small piece of hot glue or silicon
Install actuator and test

I have done this repair upside down in the passenger seat while we were driving
I have used it a few other times over the years to fix blend door axles that look EXACTLY like yours

Also since your limited has eatc make sure you do a self test and clear any codes

Copy that. Thanks 410. I'll try that.