Ac stuck on defrost

[jk kelly]

My ac is stuck on defrost. I did change my dash out. The flapper behind the glove box doesn't change nothing when I push it in. Any ideas, it's hot here in Mississippi .....

 

[rev. 3:11]

Check your vac lines & the one-way check-valves;the little gray&black discs in-line w/ vac line
if the check-valve is leaking or vac line split then the vent defaults to the "defrrost" position
(I THINK , if I'm mistaken, we'll both know shortly...)

D

 

[jk kelly]

Check your vac lines & the one-way check-valves;the little gray&black discs in-line w/ vac line
if the check-valve is leaking or vac line split then the vent defaults to the "defrrost" position
(I THINK , if I'm mistaken, we'll both know shortly...)

D

How can you do it manual?

 

[jk kelly]

Check your vac lines & the one-way check-valves;the little gray&black discs in-line w/ vac line
if the check-valve is leaking or vac line split then the vent defaults to the "defrrost" position
(I THINK , if I'm mistaken, we'll both know shortly...)

D

Where is the gray and black disc

 

[turbo nasty]

There is 3 hard plastic lines that run along the firewall on the passenger side .....one goes to map sensor, one goes to heater valve and one goes to a 3 way plastic check valve. The 3 way valve is your a/c check valve. Common for the hard plastic lines to break and leak. The vac signal from the engine to the 3 way valve comes off the small check valve in front of the egr. Just follow the lines


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[jk kelly]

There is 3 hard plastic lines that run along the firewall on the passenger side .....one goes to map sensor, one goes to heater valve and one goes to a 3 way plastic check valve. The 3 way valve is your a/c check valve. Common for the hard plastic lines to break and leak. The vac signal from the engine to the 3 way valve comes off the small check valve in front of the egr. Just follow the lines


Posted from the TurboBuick.Com mobile app

Thanks bud

 

[Nelson Ramos]

Thanks I have the same prob.

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[belsie]

Would removal of all the metal heater lines to engine incl valve have any effect on the A/C operation? Just looking to clean up the area of clutter (don't need heater in Fl). Thanks for any input

 

[Nick Micale]

The default mode for the AC/heater is a spring loaded door that directs air to the defroster vents.

There is a vacuum diaphragm/actuator on the driver's side of the console up high that controls this door. It must have vacuum to open it, and keep it open for the dash vents air flow.

I was trying to remedy this problem on a hot air car this week, and the vac lines are a real nightmare under the hood especially, and not sure it even had vacuum to the dash?

Since AC is more important in the desert than defrosters, I ran a vac line from the actuator directly to a vac source on the engine and now have a nice, cool TR, and it did not take hours and lots of blood letting!

 

[Bruce Urie]

Nick....you are a genius! I thought of the same thing just a split second before reading your post, but you beat me to it....it makes sense to do it this way with a direct vacuum source......man, glad you are here on this board...you have helped/solved so many problems for us guys (especially this dweeb here...me) Everyone would be lost without you. Keep up the great work....you use that brain of yours so efficiently!

Bruce '87 Grand National

 

[jk kelly]

Nick....you are a genius! I thought of the same thing just a split second before reading your post, but you beat me to it....it makes sense to do it this way with a direct vacuum source......man, glad you are here on this board...you have helped/solved so many problems for us guys (especially this dweeb here...me) Everyone would be lost without you. Keep up the great work....you use that brain of yours so efficiently!

Bruce '87 Grand National

I found my problem.. When I took my ECM out I guess I pulled one of the vacuum lines off that go to the firewall and hook up to the connector that feeds Tito under the hood. Plugged it back in and problem solved. Thanks for All the input guys!!

 

[milehighttype]

Thanks Nick! My car is doing the same thing. Chasing vacumn lines on a hot air is a nightmare....

 

[salvageV6]

The door is controlled by the upper mode vacuum motor.

The feed to the A/C control head is the purple hose above the radio.

It comes straight from the vacuum ball under the drivers fender, check for vacuum on that hose first. It should be there at all times with the car running.

The blue hose on port 9 of the A/C control head goes to that upper vacuum motor, check it for vacuum in the A/C or vents positions.

This assumes a C60 manual system not the C68 electronic one.

There's no reason not to fix the stuff right, it might be easier than running a new source to the upper mode vacuum motor.

 

[Roc87]

Some good stuff here, subscribed