Only blows through upper dash by speakers - Third Generation F-Body Message Boards

Mrgref92 · 07-20-2009, 09:21 PM

My a/c heat only blows through the upper dash towards the windshield, it doesnt go through any of the middle vents, I just got the blower motor working, any ideas?,

and also I need to recharge my system, can I just use r123, because it originally took r12, and can someone just explain briefly on how the a/c works, like what the compressor does and the evaporator.

Also Which port is the lower service port because when I need to recharge it I dont want to get the wrong port, thanks

NINÅ · 07-23-2009, 10:32 AM

The blend door(s) is not working.

It’s powered by vacuum.

Pull the HVAC panel and see if the vacuum hose is giving vacuum.

If not trace it back to the engine to find where the break is.

About refrigerant changing:

You should have the system evacuated.

Then add 8 ounces R123 compatible oil:

4 ounces directly into the compressor, then turn the compressor several revolutions by hand.

The balance of the oil into the refrigerant port.

Obtain a set of pressure gages (you‘ll need them anyway).

They should be marked HI and LO sides.

The HI and LO sides have different size inputs which makes it improbable to get it wrong.

Happy Racing!

If People Drove Any Slower They’d Be Going Backwards

Fog lights are not driving lights. They look dorky. Turn em off slow pokes.

How bout those dorks too scared to drive without headlights on in the daytime!

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JamesC · 07-23-2009, 12:24 PM

with the vac problem. Defrost is the default.

JamesC

Mrgref92 · 07-23-2009, 12:46 PM

Sorry what's the HVAC panel?

Is it the knobs in the middle controling the airflow?

JamesC · 07-23-2009, 12:56 PM

Quote:

Originally Posted by Mrgref92

Sorry what's the HVAC panel?

Is it the knobs in the middle controling the airflow?

Yes. The panel controls fan speedo, heat, AC, etc.

JamesC

Mrgref92 · 07-23-2009, 01:04 PM

Well I took that apart the other day and everything looked normal,but I wasn't sure where the vaccum lines were

JamesC · 07-23-2009, 01:17 PM

Quote:

Originally Posted by Mrgref92

Well I took that apart the other day and everything looked normal,but I wasn't sure where the vaccum lines were

Here's a pic:

http://www.thirdgen.org/techboard/at...duct010707.jpg

Turn the controls on and stick an ear to the pass side of the unit. If you hear hissing, you've found your problem.

JamesC

LoudmouthSS · 07-23-2009, 01:20 PM

its more then likely the vacuum acutator wheel on the back of the heater controls. If you pull them forward you can see where the vac lines all meet at the back of the heater controls, what they are attaching to on the panel is the actuator wheel, they usually fall apart after some years. take the lines off you the wheel just pops off. I got one at advance awhile back but since then i think they stopped selling them.

JamesC · 07-23-2009, 02:27 PM

Quote:

Originally Posted by LoudmouthSS

its more then likely the vacuum acutator wheel on the back of the heater controls.

If that's what it is, then I "believe" this is what you need: Valve Vac Sel GM part # 16032395. The number is good on GMPartsDirect.

JamesC