How is everybody? I've been reading this forum for a couple of weeks now and you all seem to know your way around the vettes!!

I did a search through the forums on this. I found a few bits and pieces of information, but nothing rock solid. Ok here's what I got:

When I turn my A/C on, it will work, then turn hot. So, I removed the blower control module unit under the hood, on the passenger side. Looked in there and had my g/f turn on the air. The door didn't move. I stuck a screwdriver in, and it moved freely.

So I read that there's a plastic retaining clip on the rod thats on the door.

So, at work, I removed the shroud (pain in the butt by the way) and saw that there was a white plastic clip on the top on the rod.

Is there another retaining clip underneath?

Is this that big of a job, removing the dash components under the passenger side?

If so, I think I might replace the heater core while I'm tearing all that out just because of the horror stories I've heard.

It reached 90 here today, and I can't take sporadic air conditioning!! Any and all feedback/information is going to be helpful. Thanks in advance! :cheers:

Few more bits of info. This is an 88 with the Digital Controls, and the temperature setting has been flicking on an off for some time. Once, again any help would be greatly appreciated!


[Modified by 88vettelover, 1:30 AM 5/7/2004]

 

Its sounds from what you are saying that your AC blows cold...then turns hot...then turns cold...if this is correct you may need a recarge of freon :yesnod:

 

The door should move as the temp controls are switched between 60 and 90 with it on auto. It's controlled by a motor above the passenger side hush panel. That's held in by 3 sheet metal screws so remove it and look around until you see it. The rod is connected by a plastic clip. If it's broken you've found the problem. If not, the motor may be shot or the electronic device that controls it could be wacked. Since your dash panel is flickering, you might want to check for a trouble code. Press Ext Temp and Auto at the same time and then the warm button until 08 appears. Then press warm. 00 is no faults. 01 is the fault code for the temp door. Post any other codes that show up.

 

Haven't had the air problem, but did have the flickering, just remove the control panel, unplug it and cleand the connections with electrical cleaner, that solved my problem. :thumbs:

 

I just had it recharged not too long ago. And it will continue to blow cold if I stand outside of the car and make sure the door is shut.

When I drive, I think the door is moving with every bump I hit, you know, it just moves on its own. I'll check for faults today and post what I find.

Thank you all! :cheers:

 

Ok, here's what I've found. I took off the hush panel, and looked at the door underneath along the right hand side. I had my Dad change it from Heat to A/C while I watched it. It functioned normally.

SunCr: I also couldn't get the codes? I pressed ext. temp and auto at the same time. And it came up with -01 and then I hit warm until it went to -08 and then pressed warm again and it just kept cycling through the numbers -1 through -09???? :confused:

The door I'm talking about, that isn't moving at all is the door thats located in the evaporator housing. If I remove the little controller, and watch the door, it doesn't move when I change it from heat to A/C.

But, if I turn on the A/C and reach in there with a screwdriver, and open the door, I get blazing hot heat. If I shut the door, the A/C blows cold as ice.

So what controls this door? Vacuum?

Here's some pictures: http://www.cardomain.com/id/88vettelover - the first picture in the sequence is the door under the dash, that one is functioning properly, the next one in the sequence is the shroud where the other door is located, the third one is the picture of the evaporator with the door right next to it, kinda rusty in the picture.

Thanks!

:banghead: :banghead:

 

It's called the temp door and it's controlled by an electric motor under the hush panel. The electrical harness connected to the motor has 5 wires - tan/black, yellow, dk green/white, red and black. If you can see the armature and rod moving, the door should be moving inside the evaporator housing. If not, the linkage is broken, but usually it's just the plastic clip. To test, disconnect the rod and operate it manually - door should move. After you mess with it or should you replace the motor or disconnect the electrical harness, the blower motor isn't going to work for a few minutes as the system relearns the position of the door.

On the codes, after you advance it to 08 with the warm button, hit the cold button - that will display any codes.

 

Ok, I crawled under the dash again (very uncomfortable by the way) and saw the harness you're talking about.

How do I go about testing the rod? I see that theres a 7mm screw above the harness and then the harness itself.

Do I have to drop that plastic panel down?

Maybe I'm thinking the hush panel is the one with the interior light attached to it...is that not the hush panel?

If so, I already began removing that plastic panel once, but it didn't want to come out. Maybe I'm missing something here.

Thanks for the help so far.. :)

EDIT: I just went and checked for codes, but none there. Hit ext. temp and auto at the same time, scrolled to -08 and hit cold. 00 showed up.


[Modified by 88vettelover, 11:03 PM 5/7/2004]

 

Yes, the hush panel is the one with interior light in it. It is awkward to get at the motor with the heater plenum in the way, but usually you can see it operate. Try using a mirror. If it's broken, then you may have to unbolt it though removing the plenum makes it a lot easier (if it is broken and you also need to replace the heater core, now's the time to do it!)

 

Where is the motor in location to the wiring harness/connection?

I don't understand how I could see the motor working? All I see under there is plastic and more plastic.

SunCr: I've been trying to send you some IM's, do you have them disabled? I think it would be easier to communicate that way.

Thanks for the help!
:banghead:

 

As far as I know, IM isn't disabled; however, I'm not always online.

The harness runs from the Programmer, which is above the accelerator, over to the motor. It's plugged into the motor.


[Modified by SunCr, 8:57 AM 5/8/2004]

 

I checked my Norton Internet Security and may be blocking IM - I couldn't get it to configure anything. In any event, the rod should be on top of the motor and then it runs through the heater box out to the evaporator housing. I think a mirror might really help you see it. Otherwise, you can do what I've done when I'm messing around with anything behind the dash: Remove the top cover, crash pad, and passenger vent plenum. It's a pain to take all this stuff off, but it makes getting at everything a lot easier.

 

Ok, I'm about to go at it again. I see that the harness is plugged into a black peice of plastic that covers the whole underside of my passenger side dash.

I'll snap some pictures and post them in a few.

SunCr if you're online send me an IM. Thanks! :cheers:

 

There is a black plastic vacuum check valve at the back of the passenger plenum that may need replacing. Your Cruise control also won't work if this valve is broken.

 

Is there a way to check this valve? Cruise control works fine.

I know it's that door in the shroud, I just am not sure how to go about getting to the linkage.

 

Blow into the side of the valve connected to the plenum. Air should not flow in that direction.

 

Vacuum has nothing to do with the temp door. You need to access the motor and the linkage that controls it. Can you see the two sheet metal screws that hold the motor to the heater plenum? If so, unbolt it and see if that helps you to gain access to the link rod.

 

Ok, although I'm pretty mechanically inclined, heating and A/C is not my bag of tricks :banghead:

Ok, let me review, SunCr, I found the harness you were talking about with the correct wiring. I'm assuming this is exactly where the motor is. But there is a huge plastic peice that is under there and I can't see anything around it. I see a screw above the harness, but that's the extent of it. I'm gonna go look right now as I'm posting this and see if I can see anything else.

BRB....

Ok, I can see the harness, that's it. I have a picture of it, but you can't really see anything else around it. The harness I'm talking about with the exact same wires you told me is plugged into the black plastic peice that is right next to the duct that runs from the passenger side to the driver side.

Is this right?

I only saw one screw by that harness.

For pictures go here: http://www.cardomain.com/id/88vettelover

There's a picture of the harness I'm referring too.

:banghead: :banghead: :banghead: :banghead:

 

You may need to unplug the harness, but once you do, you'll need to clear the control panel's memory to get everything working again (pull the courtesy/clock fuse), so for troubleshooting, it's best to leave it plugged in. Bolts are upper left and right and secure the motor to the heater plenum or heater core cover (7mm heads as I remember them). Link is on top passing through a rectangular opening to the evaporator case. You should be able to feel the rod and again, a mirror might help you see everything.

 

Well, I unplugged the harness...oops!! I guess I'll have to pull that fuse. Anyway, I'll try later tonight or tomorrow on getting those screws out and then looking at the linkage.

Thanks for all your help. I'll post my results! :banghead: