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2000 Eldorado ESC; 1974 Dodge Monaco 440 Police package
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198 Posts
Discussion Starter · #1 ·
Guys,
If you remember, I thought I had this fix a few months ago, but now with spring and summer on it's way (and 90+ degree temps we've been having down here), I've discovered, through usage, that the fixes I made have had no effect on this problem. To recap, I'll list what I've done:

1) Pulled the codes. These are the only ones:

U1016 - Loss of Communications with PCM
B1771 - Cassette tape slow
RFA U1000 - I have no idea what this is...it's not in the list


None of these appear to be connected with the issue.

2) Replaces BOTH actuators...a simple, quick job. The only thing I didn't replace was the wiring harness, but it looked OK.

Now here's the rub: When I turn the A/C on, and dial the knob from 60 to 90, I can watch both actuators moving through their 180-degree arcs (or whatever angle it is), the 2 vent doors appear to be opening/closing smoothly in unison, the air shunts from dash (60) to floor (90), and the temp changes as well (as it should)...BUT...I get NO cool air from the driver's side vents (or the rear backseat/console vent, either)...it's always consistently warm air, even when the pass side goes cold on 60. Also, the padded center console kick/side/knee panel is venting warm air on my right leg (which could be because of the ducting to the rear vent, I'm assuming)....the whole of the driver's lower leg area is a warm sauna. :p

Here's a few possible culprits I've entertained:

1) I've read here that it could possibly be the ACM, but I'm not sure what that even does, or where it's located...

2) I was wondering if there might be another blend door under the driver's side dash that's stuck...

3) The Temp control knob/switch in the dash is faulty (but those actuator's react, so I'm not 100% sure this is a culprit)...

I've got to figure this out, because Momma ain't happy driving around in the summer with the heat on...:devil:...and, if there is a way to jury-rig those doors temporarily, with duct tape and zip-ties, so we have a/c on both sides, I'm open to that suggestion, too, until I can fix it properly...

Any ideas?

Rob
 

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04 Deville, 11 DTS Premium, 00 Deville (sold), 02 Deville (sold)
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2,691 Posts
IMO... from your description the actuators appear to be responding to their commanded position. Which indicates both the actuators and their respective temp control switches are acting normal.

This is going to sound a little strange...
Have you checked the freon level? For some reason... don't ask me explain it. In a dual zone system the drivers side air can be warmer than the passenger side air when the freon is low.
 

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2006 XJ, 2000 Eldorado ESC--total loss :(
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1,180 Posts
I agree with 00 Deville, if both actuators (top and bottom) are moving through their full range, but the driver's side is warmer, that usually indicates low refrigerant. Probably will trip the "service a/c" message soon. For a quick check of ac performance you can feel the inlet and outlet lines of the evaporator (outlet should be as cold or colder than the inlet, both should be near freezing) with the ac running.

Also, I believe the rear seat takes air from the driver's side, so gets the same temp in the back.

The only other possibility is that even though the actuators are moving, the linkage inside the air box is broken, or the door itself is broken. The bottom actuator is for the driver's side temp. That one can break inside the box and the linkage won't move the door. Been there, done that... little plastic clip is $8 from GM. You do have to pop open the heater core cover to access that, not a difficult job at all. When you change from 60 to 80, does the driver's side air go from ambient outside air to 100* heat? If so, the door is fine, it's your ac that needs to be serviced.
 

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2000 Eldorado ESC; 1974 Dodge Monaco 440 Police package
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198 Posts
Discussion Starter · #4 ·
The only other possibility is that even though the blend doors are moving, the linkage inside the air box is broken, or the door itself is broken. The bottom actuator is for the driver's side temp. That one can break inside the box and the linkage won't move the door. Been there, done that... little plastic clip is $8 from GM. You do have to pop open the heater core cover to access that, not a difficult job at all. When you change from 60 to 80, does the driver's side air go from ambient outside air to 100* heat? If so, the door is fine, it's your ac that needs to be serviced.
BINGO! You hit the nail on the head, mh....I went out to check, and sure enough, the linkage on the lower actuator was flopping around inside the heater core cover, where it has become disconnected....No. 36 from the lower tab of No. 15 (I'm assuming) in this diagram...



The plastic clip has apparently exploded (like my top one did), and the link is no longer operating the door; I poked a long screwdriver in there, and closed or opened the door (whichever it is--I can't tell)....you can hear it 'shift', and now the a/c works fine! :bouncy:

Problem is, the blend door wont stay in that position, so I'm going to have to 'pop open' the heater core cover, as you say: To be honest, I'm not sure how to do that. I see one screw that's visible, and I'm not cherishing the idea (what I'm seeing) of having to pull the whole heater core unit out from under there to re-hook that one, single link....I can see visions of disaster looming.

Can you give me a quick run-down on the easiest way to do this, mh? I don't have a service manual, and the diagram above is the only visual resource I have (which isn't much)...:p

Thanks,
Rob
 

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2006 XJ, 2000 Eldorado ESC--total loss :(
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1,180 Posts
There you go... You need clip #2 from your GM dealer, part number 89019346. Get 2 if you also need one for the top. Brace yourself, they're $8.11 each...

The heater core does not need to be touched. Since you are looking at the actuators, I assume you have the glove box out. Remove the linkage rods from the actuators. The rod just pops out of the little white threaded clip--note about how much thread sticks out each end before removing. Then there's two 8mm screws holding cover #40 on. That will pull back just enough to see in the bottom linkage (might have to reach in and pull it into view). What you have to do is put the clip #2 into the door lever first, then stick the metal linkage into it and then it locks in.

Put the cover back on, snap the threaded rods back into place on the actuators, and you're done :)
 

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2000 Eldorado ESC; 1974 Dodge Monaco 440 Police package
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198 Posts
Discussion Starter · #6 ·
Mh...I really appreciate that info! Your super-awesomeness shines through...THE PROBLEM IS FIXED! I'm happy, but more importantly, the wife is happy! :yup:

One admission, though...since a), I don't have GM dealership close by (and 8 bucks each is a bit steep for a clip, IMHO), and b), I'm a cheapskate, shade-tree, borderline-******* mechanic, I chose to use a couple of e-clips and a couple of thick-walled, 1/8" rubber vacuum caps on the tips of each linkage rod! I tested them on my wife and son (they couldn't pull 'em off without pliers), so I knew the actuators couldn't muscle them loose..and I'm here to say that they operate flawlessly! :cloud9:

My thanks again for all the help! :D
Rob
 

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Registered
2006 XJ, 2000 Eldorado ESC--total loss :(
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1,180 Posts
Haha, well as long as it works and you're happy :) Glad I could help!

Yeah, those clips prices are way out there for $0.02 of plastic. When I went to buy mine I thought I made a mistake and walked into a Mercedes dealership ;)

And I should say thanks again to N*Caddy for his help when I had those heater core issues a few months back. I would have not had an easy job fixing that if not for his help!
 
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