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Discussion Starter · #1 ·
I am experiencing some problems with my Air Conditioning. The problem is that I can't seem to get any cold air out of the vents while I'm driving. The weird thing about it is that the air conditioner blows out really cold air while the car is in Park.

I'm not sure what the problem could be, does anybody have any idea of what the problem could possibly be?

I have also enclosed a few pics of what I think may be the problem, let me know what you guys think.

All help will be greatly appreciated.

Thanks
 

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are you saying that it blows warm air out the vents when driving, or, are you saying that it does not blow out the vents when driving which would seem to indicate a vacuum leak to me.
 

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Discussion Starter · #3 ·
Yeah, it only blows warm air out of the vent while I'm driving, but really cold air while the car is in park.
 

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I would guess one of two problems....

Is the system low on freon and cycling on and off at idle?

Or, a small vacuum leak which cuts it off when the vacuum drops in normal driving
 

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i have the same problem with mine. i narrowed it down to vac. ice cold then warm like the vent is on.
 

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I vote for a vac leak somewhere in HVAC system...
 

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I agree with Steve. It sounds like it is low on freon causing the compressor to turn off when the rpms come up. Do you have a set of manifold gauges you can put on the car? If not try revving the car in park to see if the compressor cuts off when the rpm's come up.
 

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In the 2nd pic there is vac hose missing from the upper & lower circles isnt there? Is it my poor eyesight? Seems like some vac line is missing to me?
Also, whats the round thing by tranny dipstick on heater hoses?
 

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Discussion Starter · #9 ·
Just a Six?? said:
In the 2nd pic there is vac hose missing from the upper & lower circles isnt there? Is it my poor eyesight? Seems like some vac line is missing to me?
Also, whats the round thing by tranny dipstick on heater hoses?

Yeah, you are seeing correctly concerning the vacuum hoses missing, and that's what I have been told could be the problem. As for the other pic with the "round thing by the tranny dipstick on heater hoses" I am not sure what that is exactly because I'm definitely not a car expert. I'm learning alot from these forums, and that's why I posted this question & pics.

Anybody have any ideas of what that is?

Thanks
 

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Just a Six?? said:
Also, whats the round thing by tranny dipstick on heater hoses?
Thats is his heater control valve ...Parts store replacement series.
Made out of black plastic like the f-bodies.
 

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Are you sure, Steve?

The heater control valve is shown in the picts just below the dip stick and is inserted into the water line as it should be.

I could not figure out what he had circled, nor what the line running to it is, or where it came from.

I am not familar with the F body control valves...but that does not look like water is going thru it??
 

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Yes, I was answering Just a six's question about what was that round thing on the heater hose.

But when I look at the pictures again; he has two vac. line ends that arent connected, circled. I would reconnect those and the vent selector should work again.
 

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Referring to your first picture, the black vac line that you see running along the firewall just "above" the 3 and 5 plug wires is the vac source for the HVAC controls. The vac source you have circled is the reference for your boost gauges - the white line t'd off that looks to be for an aftermarket boost gauge, and the missing line would go to the factory boost sensor.

If you had a loss of vacuum in the cabin, then the air would still blow cold, but it may blow out the floor and defrost (default positions). I agree with Steve. If it keeps blowing out the dash vents, but gets warm based on RPM, then your refrigerant is low and the compressor is cycling off.

EDIT: Now I see that another pic shows a broke vac line on the heater control valve. This is another line that should go into the cabin. The default position for that valve is hot, and vac is applied to this valve when MAX AC is on (and maybe regular AC. But with the blend door on cold, it should have a huge impact although you want it fixed. I say fix that vac line and re-assess.
 
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