No heat from heater 1990 ZR1

[jrd1990zr1]

Originally Posted by QB93Z

John,


The Blend Door is controlled by a small electric motor and uses an electronic circuit to send position feed back to the AC Programmer. When the car is first turned ON, the AC Programmer sends a sequential full heat and full cool command to the Blend Door Motor. Since you are not seeing the movement, either the motor has failed, the AC Programmer has failed, there is a wiring problem, or the door is stuck.


I haven't investigated the access to the motor on a 1990 yet, but when you get to it, you can remove it and observe it's operation not connected to the door. And you can try to move the door by turning the pivot rod.


I have a complete set of the duct work from a 1991. I did not see it in the car so I don't know exactly how much you have to take apart to get to the motor.


If you need trouble shooting help when you get to the motor, call me. I will be glad to help.


Jim
443-244-1347

Hi Jim,

I don't want to waste your time with a long phone call until I get deeper into this. I pulled the glove compartment, other than the top of the duct work not much to see Photo 1.

Pulled the lower hush panel (Photo 2 and 3) and low and behold looks like someone was there before. Radio receiver and associated wiring is all hanging loose (Photo 4). I see the duct work and the SIR wire but nothing that looks like an actuator or motor. Am I looking in the wrong places or not far enough into this?
Thoughts?

Thanks, John

[QB93Z]

John,


In your picture 1, the duct pieces you are looking at supply the air to the small vents that blow on the passengers knees. You have to remove those ducts to get to the top of the main air box that houses the Blend Door.


Keep digging and send another picture so I can get oriented with the 1990 setup.


Jim

[Dynomite]

Originally Posted by jrd1990zr1

So Doug have you ever pulled the glove box to get the the heater box??
John

Just in case you want to pull your heater core without pulling the Dash.....
Replacing the Heater Core and Heater Hose Connection

[Mystic ZR-1]

Originally Posted by jrd1990zr1

So Doug have you ever pulled the glove box to get the the heater box?? Before I start ripping and tearing thought I would ask. How was Carlisle, wish I had gone.

John

Hi John
Fortunately, no! Never had to go in there.
Good luck with yours.
Missed ya @ Carlisle, nice time was had by all!
D

[QB93Z]

I just remembered something about the HVAC system that affected my trouble shooting. The HVAC programmer needs to be powered off (Battery disconnected) after any changes you make to the system.


You may want to try disconnecting the battery now and see if the system returns to normal operation.


Jim

[jrd1990zr1]

Originally Posted by QB93Z

I just remembered something about the HVAC system that affected my trouble shooting. The HVAC programmer needs to be powered off (Battery disconnected) after any changes you make to the system.


You may want to try disconnecting the battery now and see if the system returns to normal operation.


Jim

Thanks Jim, I'll give that a try.

Had to but it back together so I could get the mandatory annual NYS inspection. While driving there it set a Code 09 on the AC, low freon, so looks like I have a slow leak. Last charged it 2 years ago. No heat and no A/C.

Looks like I've got a couple winter projects.

John

[jrd1990zr1]

Originally Posted by Dynomite

Just in case you want to pull your heater core without pulling the Dash.....
Replacing the Heater Core and Heater Hose Connection

Since it looks like you have had your 1990 apart some questions on the heater core removal.

If you remove the heater box from the inside can you access the blend door actuator to replace it?

Did you have to remove the fuse panel to access the heater core box?

Thanks for the information. John

[jrd1990zr1]

So I am back to trying to find the actuator for the blend door. I've removed the dash pad, lower hush panel, console trim panels, etc. Bought a fiber optic scope and still can not find the actuator.

Per the service manual, it looks like I need to remove the distribution duct which involves removing the fuse panel and instrument panel. Before I go forward I have to ask, does anyone have a better way to get to the blend door actuator rather than removing the entire instrument panel?

Below are photos of where I am now. I am really stuck, so please let me know how you have changed out the blend door actuator on a 1990.

Last question is the lower blend door pivot where the read arrow is pointing in the third picture?

Thanks

[Dynomite]

Originally Posted by jrd1990zr1

Since it looks like you have had your 1990 apart some questions on the heater core removal.

If you remove the heater box from the inside can you access the blend door actuator to replace it?

Did you have to remove the fuse panel to access the heater core box?

Thanks for the information. John

I am not sure about the blend door but the CDM had to be removed....not the fuse panel.

[QB93Z]

Top of blend door duct from a 1991



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