mwm1993

Today I pulled the blower motor out of my car to get a look at the heater core and see whether the blend door is moving. I'm just trying to narrow down the root cause

Pics of the heater core looking from the blower motor opening:


Cleaned out most of this junk before putting back together


My big question is here:


Is this the blend door? It did not move regardless if the temp was set to 60 or 90. When the car is warm both heater core hoses are nice and warm so I *think* there is water flow

I haven't received my fsm yet but I'm enjoying working on the car when I have time and want to have as much as possible fixed before it goes into winter storage

gdl2165

Yes, that would be the blend door. Your profile says you have a 1980 and a 2011 so I'm guessing this is a new-to-you car. Not sure what year this one is but there was a good writeup recently on changing the blend door motor on a 95. The earlier C4s may be similar so maybe this will help in any case.

https://www.corvetteforum.com/forums...-corvette.html

mwm1993

Car is a 94, I'll add it to the profile in just a minute. I did read your post from a day ago and just wanted to make sure my diagnostics were somewhat sound before removing the actuator. One more question then. Do you think having the blower motor disconnected could have caused the door to stay closed regardless of the temp setting?

gdl2165

I don't know if having the motor disconnected would keep the blend door from actuating, that's actually a very good question. Is it possible to just set it in the vicinity and plug in the wires? Maybe someone else who knows for sure can chime in.

Cliff Harris

If your picture is from the blower side then you're looking at the evaporator. ALL air goes through the evaporator first and then either continues on into the HVAC ducts (in cool mode) or goes through the heater core (in heat mode). The temperature blend door determines the route that the air takes.

The blend door is controlled by the HVAC programmer, located above the gas pedal. It is operated by an electric motor, so no vacuum is involved.

john6277

had the same issue with my 95 coupe. Removed the electric motor (located inside the cab,right above your passenger's feet, behind the large plastic cover) for the heat blender door shaft. The motor has only 3 bolts to remove and you can check to see that you can operate the blender door shaft by hand and see if this improves your heat flow. New motor is $100 from Ecklers - don't try to fit in the $50 Dorman replacement. Easy project, 1 hour tops. All the best, John PS check out my post one year ago on 1/6/15 n which provides more details on this. Just click to the left on john6277 and scan my earlier posts for this info.

mwm1993

I do have heat now after replacing the blend door actuator yesterday. I added some pics to the above mentioned thread to aid in diagnosis for others having a similar issue