no cold air

[Blue85]

J
Yes, it's vaccuum actuated so when you move the levers around, the blending door will allow warm air in, cool air in or a comination of those. They are on a mechanical, threaded arm.

IIRC, the blend door is cable actuated from the temp slider on the dash. The selection of where the air blows from and fresh/recirc are done with vacuum actuators. If the temp slider is really easy to move, something has probably broken.

I repaired that plastic clip a few years back with epoxy and a wrap of stainless shim I found in my scrap bin. Better than new and no waiting for parts after tearing it down.

 

[dwnhiller93]

Yes, the temperature slider is really easy to move. It feels like its free, nothing restricting it.
And my defrost works really well. That isn't my problem. The problem is temperature controls.

 

[British Slave]

Yes, the temperature slider is really easy to move. It feels like its free, nothing restricting it.
And my defrost works really well. That isn't my problem. The problem is temperature controls.

That's how the temp slide should be. All it does is open or close a door to direct the fan to the heater core or AC evap.

 

[dwnhiller93]

OK, odds are it's the plastic link. You will need to remove the glove box. Look from the passenger side under the dash, and you will see part of the vent ducting that is held with two screws, one on each side at the bottom and one screw at the top. This is what takes air to the dash vents. Remove this vent. Then look at the link. It will be obvious if it's broke. DO NOT TRY TO OPEN OR MOVE THE AIR DEFLECTOR OR YOU WILL BREAK IT! Get the link and then come back on this thread and I will be happy to tell you how I replace them. There is a pin that has to be removed and it can be a PITA.

took off that part of vent ducting that was held by two 8mm bolts and the plastic link is not broke

 

[mrluhman]

My white plastic link isn't broken either so I can cross that off. The temperature setting is working as well. It seems like the settings are one off. No air really circulates through the dash vents and like stated, nothing on defrost. Do I need to just troubleshoot the vent connectors? I did replace the heater core recently. Could that have something to do with it?

 

[British Slave]

My white plastic link isn't broken either so I can cross that off. The temperature setting is working as well. It seems like the settings are one off. No air really circulates through the dash vents and like stated, nothing on defrost. Do I need to just troubleshoot the vent connectors? I did replace the heater core recently. Could that have something to do with it?

Put it in A/C mode and see if the heater door closes. If not it may be the vacuum motor that closes the heater door. With the vent removed, you can see it close. And that vac motor can be changed without removing the case. It's a PITA but it can be done.
What I do is hook a hand vacuum pump on the motor and see if I can make it work. If not it's probably bad. It would be #53 in the schematic.

 

[mrluhman]

The said main vent (with white connector) is as follows; open when cluster is set to off, closed on max and norm ac, slightly open on bi level ac, closed on vent, wide open on heat and defrost.

 

[Deuling]

When I bought my truck I discovered none of the vacuum lines were hooked to the vent system... well snow was coming down so I needed defrosters so i zip tied that door so only my defrosters were open lol, it works and all i need to do is cut that zip tie if I want the vents open... A little bit of riggerin but oh well, nobody can see the black zip tie under the dash anyways lol.

 

[mrluhman]

When I bought my truck I discovered none of the vacuum lines were hooked to the vent system... well snow was coming down so I needed defrosters so i zip tied that door so only my defrosters were open lol, it works and all i need to do is cut that zip tie if I want the vents open... A little bit of riggerin but oh well, nobody can see the black zip tie under the dash anyways lol.

I am all for functionality but I am just desperate to get this right. There is so much money into this rig that it makes me wish I never even started this project. I am taking all the dash component guts out to troubleshoot the problem and I am making things worse. I took off the speedometer and it looks like I broke off the needle. It was a well working gauge and now I have to deal with the odometer not being accurate on the replacement. Should I look at the Dakota digital one since my ability to verify the mileage is screwed anyways? I took pictures so I can prove actual mileage but what a kick in the nuts when I am just trying to fix something completely unrelated.

 

[dwnhiller93]

My white plastic link isn't broken either so I can cross that off. The temperature setting is working as well. It seems like the settings are one off. No air really circulates through the dash vents and like stated, nothing on defrost. Do I need to just troubleshoot the vent connectors? I did replace the heater core recently. Could that have something to do with it?

Seems like we have exact opposite problems lol

 

[y5mgisi]

Dang! Subscribed! Good info here.

 

[jeff in co]

I am all for functionality but I am just desperate to get this right. There is so much money into this rig that it makes me wish I never even started this project. I am taking all the dash component guts out to troubleshoot the problem and I am making things worse. I took off the speedometer and it looks like I broke off the needle. It was a well working gauge and now I have to deal with the odometer not being accurate on the replacement. Should I look at the Dakota digital one since my ability to verify the mileage is screwed anyways? I took pictures so I can prove actual mileage but what a kick in the nuts when I am just trying to fix something completely unrelated.

PM at you....

 

[British Slave]

The easiest way I have found to troubleshoot the heating/AC is to remove the glove box and dash pad. With the dash vent piece removed, then you can operate each mode of the ac and see whats happening. Mine originally only had air blowing out the floor vent. I found the plastic link broken, replaced it, then found the defrost vacuum motor bad. Repaired it. Then I dumb assed the temp deflector and broke it. Now I'm waiting for the mood to hit me to pull the whole case out and replace it with the one on my bench.

 

[British Slave]

I am all for functionality but I am just desperate to get this right. There is so much money into this rig that it makes me wish I never even started this project. I am taking all the dash component guts out to troubleshoot the problem and I am making things worse. I took off the speedometer and it looks like I broke off the needle. It was a well working gauge and now I have to deal with the odometer not being accurate on the replacement. Should I look at the Dakota digital one since my ability to verify the mileage is screwed anyways? I took pictures so I can prove actual mileage but what a kick in the nuts when I am just trying to fix something completely unrelated.

I think you can replace the needle.

 

[mrluhman]

The easiest way I have found to troubleshoot the heating/AC is to remove the glove box and dash pad. With the dash vent piece removed, then you can operate each mode of the ac and see whats happening. Mine originally only had air blowing out the floor vent. I found the plastic link broken, replaced it, then found the defrost vacuum motor bad. Repaired it. Then I dumb assed the temp deflector and broke it. Now I'm waiting for the mood to hit me to pull the whole case out and replace it with the one on my bench.

Everything is removed including most of the instument panel so I will see what I can see.

 

[mrluhman]

I think you can replace the needle.

That would be the easiest. Anybody ever do this? Better question does anyone have a 89 or earlier speedo that I could buy to pilfer the needle from?

 

[British Slave]

That would be the easiest. Anybody ever do this? Better question does anyone have a 89 or earlier speedo that I could buy to pilfer the needle from?

I have one that could be bought real cheap, but try your Chevy dealer, they may have it.

 

[dwnhiller93]

what to do now that that plastic link isn't broke?

 

[British Slave]

what to do now that that plastic link isn't broke?

On the very end of the case (left end as you are sitting in the seat) there is a vacuum motor. Pull the hose off and use a hand vacuum pump to see if it works. You should be able to pull and hold a vacuum. If not it's bad.

 

[dwnhiller93]

On the very end of the case (left end as you are sitting in the seat) there is a vacuum motor. Pull the hose off and use a hand vacuum pump to see if it works. You should be able to pull and hold a vacuum. If not it's bad.

took me forever to get a vacuum pump and get it done. today i had some time to see if it was holding vacuum. and it is holding it. so any ideas on what to check now? i really would like to get it working.
thanks for your guy's help.