HVAC stuck on defrost.

[cutlasssupremepizza]

I have a really odd HVAC panel in my 95 CS.

 

It is not the dual zone, but it is not vacuum, as it's all wires behind it.

 

Air is stuck at defrost. Fan speed and hot/cold work fine.

 

Thought maybe faulty switch, replaced with a JY one same deal. Checked all fuses.

 

It sounds like the door is not wanting to open, can hear a faint electrical noise like it wants to.

 

Any other ideas? I have a feeling its the mode door. I hope not, because I don't wanna tear out the dash to fix it.

[cutlasssupremepizza]

Ok...it appears this is an electrical/vaccum setup?

[GOT2B GM]

Check for a vacuum leak on the line going to the vacuum ball

 

Sent from my Z30 using Tapatalk

[Nas Escobar]

Ok...it appears this is an electrical/vaccum setup?

 

It's not a mechanical control panel if that's what you mean. The reason you saw nothing but wires is because all the operations are done electrically. There is still a vacuum setup to operate the actual A/C system but the commands are electrical.

[Schurkey]

Common as dirt for the vacuum hoses to break (brittle plastic) and then the HVAC is stuck on defrost and the cruise control doesn't work.

 

I've fixed brittle hoses behind the engine, near the cruise servo, and under the battery on my '92 and '93 Luminas.

[cutlasssupremepizza]

Well the hose runs from a T leading to a vac booster (cruise is all electronic) to the firewall, to a rubber fitting on the upper area of the footwell near the electrical hull fitting.

 

Well, it appears there is a vac leak, but geniuses at GM decided to run the vac line in the middle of the wire harness going into the fire wall.

 

I'm going to have to run a new vac line into the firewall, but there appears to be no plugs in it.

[95 vert]

So the vacuum line from the "ball" (storage canister below the battery) is good from the canister up to the "T"?

I usually find it broken near the corner of the battery

[cutlasssupremepizza]

As far as I know. Where can one get vacuum line?

[cutlasssupremepizza]

Well now I am officially pissed.

 

I replaced the vacuum line going into the car, and there is a right angle fitting before it goes up into the dash, and I have good vacuum there.

 

I checked all the fuses, and they are good.

[Heartbeat1991]

The leak could be in the dash somewhere. It is possible that the controls aren't working correctly, too.