No heat from heater 1990 ZR1

[QB93Z]

I just posted a picture of the top of the duct where the blend door is located. The duct I have came from a 1991 ZR-1.


In the photo there is a small rectangular opening that reveals the upper edge of the blend door. The blend door motor is not installed in this picture. The pivot is towards the front of the duct relative to the small opening.


The photo is oriented as if you were in the passenger seat looking down on the blend door duct.

[QB93Z]

Bottom of blend door duct. The blend door is facing the concrete in this pic.



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[jrd1990zr1]

Originally Posted by QB93Z

Top of blend door duct from a 1991



Sent from my iPhone using ZR-1 Net Registry

Jim,

I can see the white thing that looks like an intake with my fiber optic scope. Next to it is something with the # 145772 as best as I can read it. Photo of the tag is blurry, sorry. Can you tell if your 1991 box splits in half to access the actuator or can this box be removed from the inside of the car in one piece?
I am trying to avoid pulling the entire IP which is the process the Service manual directs you to to remove the air duct which is one piece across the entire width of the car. I am wondering if I pull the blend box which seems like it splits at the firewall could I then get to the actuator? I've got to believe someone must have done this on a 1990 before me. Thanks again, John

[QB93Z]

John, I will take some better pictures tomorrow morning. Jim

[jrd1990zr1]

After two weeks of working on it, I finally got the heater core box(and actuator) removed from the car. Had to remove nearly the entire right side dashboard, high level fill, Part of the AC evaporator, fuel lines, wiper reservoir. Here is the offending part. Now I have to find a 94-95 heater core box to replace the 1990 box.

[jrd1990zr1]

So I got the bright idea (or may be not so bright) to swap out the 1990 Heater Core box with a 1994 heater core box. This would move the actuator from the top to the bottom of the heater core box. I was told on the Corvette Forum that a guy on there did this and it only required the use of a 1994 heater box, actuator and the short harness. I have a 1994 GM 16124952 actuator and the small harness from a 1992. In comparing the electrical schematics for the 1990, 1992 and 1994 model year there is no difference in the 3 harnesses other than wire color.

So before I start to reassemble the car is my conversion plan possible? Are there differences in the AC controller of a 1990 verses a 1994 which would cause this not to work? Or should I just get a new 1990 actuator and reinstall the 1990 heater box. I am at a loss on how to proceed.

Anyone who who has done this on a 1990 knows how long it takes and the PITA this job is. Your thoughts please.

Thanks,

[WVZR-1]

Originally Posted by jrd1990zr1

So I got the bright idea (or may be not so bright) to swap out the 1990 Heater Core box with a 1994 heater core box. This would move the actuator from the top to the bottom of the heater core box. I was told on the Corvette Forum that a guy on there did this and it only required the use of a 1994 heater box, actuator and the short harness. I have a 1994 GM 16124952 actuator and the small harness from a 1992. In comparing the electrical schematics for the 1990, 1992 and 1994 model year there is no difference in the 3 harnesses other than wire color.

So before I start to reassemble the car is my conversion plan possible? Are there differences in the AC controller of a 1990 verses a 1994 which would cause this not to work? Or should I just get a new 1990 actuator and reinstall the 1990 heater box. I am at a loss on how to proceed.

Anyone who who has done this on a 1990 knows how long it takes and the PITA this job is. Your thoughts please.

Thanks,

I believe you take the actuator from the '94 and use it with the original '90 assembly. I believe that you need a control, programmer and a harness to invert the assembly as you mention.

This is I believe a part # progression on the actuator 16141439 changed in 4/90 to 16145772 then to 16124952 4/92. There was some vendor changes I believe through the years and much bad stock with various numbers and lots of confusion.

If you've product with either of those numbers you'd be good I believe for any year, top or bottom so long as the control, programmer and harness match.

There's a later GM# 89018368 that is in the supersession chain but when used on other applications has met with random success. If you were to buy and want to try I'd confirm returnability if it didn't work.

[-=Jeff=-]

Here is QB93Z's thread of his replacement of the blend door motor

http://www.zr1.net/forum/showthread.php?t=27542

[jrd1990zr1]

Originally Posted by WVZR-1

I believe you take the actuator from the '94 and use it with the original '90 assembly. I believe that you need a control, programmer and a harness to invert the assembly as you mention.

This is I believe a part # progression on the actuator 16141439 changed in 4/90 to 16145772 then to 16124952 4/92. There was some vendor changes I believe through the years and much bad stock with various numbers and lots of confusion.

If you've product with either of those numbers you'd be good I believe for any year, top or bottom so long as the control, programmer and harness match.

There's a later GM# 89018368 that is in the supersession chain but when used on other applications has met with random success. If you were to buy and want to try I'd confirm returnability if it didn't work.

WVZR-1 and -=Jeff=-, Thank you for the information. Your posts made me pause and think about changing the box to a 1994 heater box. I also e-mailed Bryan Thompson at Batee about the conversion and he told me that the AC programmer and the ECU on a 1990 ZR1 are paired and I could not switch out the AC programmer, control head and heater box to a 1994 version. So it appears the best course of action is to keep the 1990 intact as a 1990.

I have a used GM 16124952 actuator so I am going to try it on the 1990 heater box before I put it back in the car. If this does not work, I spoke with AC Delco and they crossed GM 16124952 to AC Delco 15-71937 which I can still get from their central warehouse. I will get a new actuator and try that. If it still doesn't work I am going to pull the AC Programmer, control head and actuators and send them to BATEE for bench testing. Bryan has graciously offered to check out the components to locate the problem.

Thank you for your thoughts above.

[-=Jeff=-]

Interesting Comments by Bryan,

My friend's 1990 had an issue and I think a programmer from a 95 or 96 worked..

Also I think the control heads were all the same, sans the color changes