Can't Change Vent/heater Controls ...vacuum Line?

[rob1231]

I searched, and nothing came up for the problem I'm having.

 

Today when I wen"t out to start my truck the windows were fogged up fairly bad, so I put the knob on defrost/floor and went inside to get ready for work. Ten minutes passed, I went outside and the windows were still fogged up! I then noticed that it wasn't blowing out of defrost but instead the dash vents. No matter where I turn the knob, air continues to blow through the dash vents. I couldn't drive my truck to work today because of this. Any ideas? I really would like to save some $$ and do the repair myself if possible. If it is the vacuum line, where is a common place for it to break? and does anybody have a picture or diagram of it?

 

Thanks!

-Rob

 

Edit - Oh, and I read somewhere, if its the vacuum line it would normally default to the floor and defrost, which isn't bad considering that's all I use most of the time, except its not and instead stuck on the dash vents. More than just five bucks worth of hose?

[redvett]

GM hasn't used vacuum since 1987 and all GMT400-800-900 use all electronics. Have someone with a Tech 2 check it out.

[rob1231]

my parents had a '02 Gmc Safari and ended up having to replace the vacuum hose in that for the heat...so yeah, they still use it

[RAF]

I had the same issue in my truck for 2 days and it went away. Even when it did for those two days most of the time when I shut the truck off and started it back up again the issue was gone.

Hope that helps in anyway.

[redvett]

A '02 Gmc Safari is NOT a GMT400-800 or 900 and yes the Safari used vacuum but it was introduced in 1985 and the HVAC was not changed, it was discontinued in 2005.

 

my parents had a '02 Gmc Safari and ended up having to replace the vacuum hose in that for the heat...so yeah, they still use it

[Gone Again]

Your control is electronic. Try disconnecting the battery for a few minutes. I've seen this work in the past. If not-you should have it checked out instead of just throwing a new control module at it.

[rob1231]

A '02 Gmc Safari is NOT a GMT400-800 or 900 and yes the Safari used vacuum but it was introduced in 1985 and the HVAC was not changed, it was discontinued in 2005.

 

Thats not what you said, you said "GM hasn't used vacuum since 1987 and all GMT400-800-900 use all electronics. From what you said, i took it as gm stopped using it in '87, which is NOT true. I have a friend with a reader, i'll see what comes up.

 

 

 

Raf and gone again, thanks I'll try disconnecting the battery and see if that works!

[[email protected]]

disconnecting the battery or doing a relearn of the HVAC doors is also a common problem.

[rob1231]

how would I do a relearn of the hvac doors? Dealer trip? I'm thinking of going in tomorrow to see what they think is the problem. I have the battery disconnected right now, so I'll wait and see if that fixes the problem.

[rob1231]

can't find the problem. I've done the reset countless times and nothing, so i made an appointment at the dealership to get it fixed on Wednesday. I'll post what the problem is and how much once its finished. I hope they use enough lube.

[rob1231]

dealer tech found a wire stuck in some gears for the defrost/floor actuator. Said it was probably from the first owner (was a lease before I bought it) and he had an electric start installed before. $130 for them to take a wire out of a gear...ouch.