randalls9

I am trying to replace a faulty heater blend door actuator on my 93 C4. I have thee dash removed on the pass. side and the heater core is out as well (leaking). I can see the blend door and the actuator on top of it, but cant seem to figure out how to remove it. It seems that I might have to remove some parts from the firewall side (evaporator area) to access some screws holding it in palce. Anyone ever done this before on this year model?

THX

t384

The motor for the blend door is underneath the dash. You will have to stand on your head some, but if I remember correctly it's only three screws and the plug. Shouldn't take more than 45 min to an hour to do.

helphos

Randalls9- any updates??
Anyone else want to weigh in on replacing the Blend door Actuator?

My recently acquired '93 has a stuck blend door (100% on heat).
I'd like any help I can get, especially after reading the FSM which suggests a complete disassembly of the car!

I'd like to think that removing the knee panel on the passenger side along with the commitment to painful scraped forearms would result in successful removal and replacemnt.

Somebody must have done it!! Time to come clean and reveal your secret to the rest of the world.

Thanks!

Paul

SunCr

Actuator for your Year should be a gear which is more than likely stripped. You simply unbolt the motor and it comes with it. Someone around here actually found the gear, but it's usually included with a new motor.

jeffp1167

The evaporator core case has to be removed there will be like 3 bolts that thread into the heater core box. Once you remove them you can pull the heater core box out and change the blendoor motor. This is the ONLY way to access the 3 blendoor motor screws. Trust me I tried every imaginable way.

you might be able to split the evaporator core case and access the bolts that way to.

this is a 1990 by the way so probably the same as your 93



here you can see one of the 10mm bolts that screws into the heater core box to the right of the heater core pipes.

jeffp1167

heres another pic of the bolts in question. Maybe with the heater core out you can reach through the vent door and loosen the bolts I am not sure. This was all removed on my 90 for complete a/c replacement but there is definitely 3 bolts that hold the box to the firewall

jeffp1167

circled in red is the approximate location of the 3rd bolt. there might be a 4th I just can't remember.

good luck

helphos

[QUOTE=jeffp1167;1575655643]The evaporator core case has to be removed there will be like 3 bolts that thread into the heater core box. Once you remove them you can pull the heater core box out and change the blendoor motor. This is the ONLY way to access the 3 blendoor motor screws. Trust me I tried every imaginable way.

you might be able to split the evaporator core case and access the bolts that way to.
-----------

Thanks, Jeff. I'll go digging in to the FSM to see what's involved in getting the evaporator core case out. I assume I'll need to disconnect the AC lines as well as drain the antifreeze before I get started.
Now I understand why some folks are putting in a manual choke cable to move that door from heat to AC.
Did you do the work yourself?? How long was your car laid up?

Thanks again. ANd thanks to SunCR for the tip on the gear. It's all in getting to the point of being able to look at that gear!!

jeffp1167

[QUOTE=helphos;1575664971]No you leave the a/c system connected !!!!!! ret getting at the bolts through the blend door after the heater core is removed. If that doesnt work split the case and then you can get at them .... to do it is about a 1-2 day job

Comanche400

I was able to replace the blend door motor without removing anything from under the hood. I made a special wrench out of an old 7mm socket and some flat metal band. The tool reaches behind the motor and can access the rear screw for it's removal. I was able to re-install the rear screw with the tips of my fingers, then used the wrench to turn it down the rest of the way.

Pingman326

Could give more details or some pics? I need to check the door on my 93. I removed the passenger seat so i could see what was up under the dash and I didn't see anything like what everyone is describing.
Thanks

helphos

Me Neither! On some years, it seems the motors may have been on the bottom of the heater box, but not mine (93 Vert). I tried everything to see it, or try to feel around for it. No luck.

The solution? I took it to my local Corvette expert- Tony's Corvette Shop.
They solved the problem and got it working, and I didnt end up with a broken back from trying to twist into a space not designed to be accessed by mere mortals. I only wish they had taken pics!
Now the blend door (and the temperature) responds to my inputs on the climate control panel. Thank goodness!



Good luck!

Cliff Harris

We've got lots of pictures of the early blend door motor (I even posted some myself).

We need pics of the later version so folks can see what they're up against when doing this job.

93 ragtop

I wanted to add a few things to this post and hopefully it will help someone.
1. The location of the motor changed from 93 being located on top to 94 being located on bottom. The attached link talks about that.
http://forums.corvetteforum.com/c4-t...n-my-90-a.html





2. Years ago, I printed this drawing that was referenced in the above link. I have no experience with trying this but I am thinking about doing it when I replace mine. Here is the drawing


Hope this helps.