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Topic: New guy with new problem! (Read 1434 times) previous topic - next topic

New guy with new problem!

First I would like to say hello! I am happy that I have found a cool site dedicated to T-birds and Cougars! Also, don't let the fact that my screen name is 871Chevelle fool you, I am a bigtime Ford fan as well!
 Anyway , I am having a little issue with my Cougar and thought that this would be the perfect place for some suggestions! So here it goes...

 I have a 1993 mercury Cougar XR7 with a 3.8L v-6, and a AOD trans. I bought this car brand new in 1993 and have had no issues with it untill now. Heres the problem ...

The heater and a/c work fine, but comes out on defrost and floor only, and will NOT come out of the dash vents..  I know it is vacume operated, so I removed the controls and glove box to check for vacume, and it pulls strong.
When I turn the controls to a/c or vent, I hear a constant 'hissing' sound like there is a vacume leak. When I select any of the heat options, the 'hissing' sounds goes away, reguardless of what I have the settings at, the blower motor will only push air through the defrost or floor vents, and not the dash vents.
I inspected every inch of the vacume hoses both under the hood and behind the dash and everything looks perfect.
Is it possible that the actual heater control assembly is bad? Or is there some sort of blend motor or something somewhere?
What would cause the air NOT to come out of the dash vents, but only the defrost and floor?
Thanks so much in advance

New guy with new problem!

Reply #1 –
It comes out the same no mater where you set the selector, even if it's just set to one position
[SIGPIC][/SIGPIC]
***** Project "EVOLUTION" 1987 Cougar LS  & 1985 Cougar Convertible *****
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5.0 HO 306 roller block, machined GT-40P heads, Wiseco dished forged pistons, Eagle forged floating I-beam connecting rods, Lunati pushrods, ARP bolts, Scorpion aluminum 1.6 rockers, Comp Cams Magnum 266HR, Explorer intake, 65mm TB, MAF Conversion, 19# injectors, Ford Racing stainless P-headers, 2-1/2" cat-less exhaust w/ Flowtech Afterburner lers , SC AOD with 2800 BDR torque converter, 3.73 T-Lok rear, CHE rear control arms, full 2-1/2" frame w/1" jacking rails & seat supports, Rear disk brakes, Turbine wheels, All original interior w/ floor shift upgrade .......
Pretty much every panel on my 87 is new, rebuilt, or re constructed. :D
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New guy with new problem!

Reply #2 –
Quote from: daminc;221044
It comes out the same no mater where you set the selector, even if it's just set to one position



It does? So when I set the controls for the air to come out at the floor, it's supposed to come out the defrost vent? And when I turn the a/c on, it's supposed to come out the defrost vents instead of the vents on the dash? I never seen anything like that before. For the first 14.5 years I have owned the car, its always come out where I selected ... Defrost, floor, or vents. Your saying that its supposed to come out the defrost only? If thats the case, I want to break it like it was for the first 14.5 years! :confused:

New guy with new problem!

Reply #3 –
I think he forgot the question mark - trying to get more info :D
11.96 @ 118 MPH old 306 KB; 428W coming soon.

New guy with new problem!

Reply #4 –
The vacuum selector switch possibly?  It should have a line running to it.....I believe it's behind the heater control assembly.
-- 05 Mustang GT-Whipplecharged !!
--87 5.0 Trick Flow Heads & Intake - Custom Cam - Many other goodies...3100Lbs...Low12's!

New guy with new problem!

Reply #5 –
Sorry, I forgot the ?
It does sound like the vac. selector. It could be why it's hissing too.

BTW.... Welcome aboard
[SIGPIC][/SIGPIC]
***** Project "EVOLUTION" 1987 Cougar LS  & 1985 Cougar Convertible *****
[/COLOR]
5.0 HO 306 roller block, machined GT-40P heads, Wiseco dished forged pistons, Eagle forged floating I-beam connecting rods, Lunati pushrods, ARP bolts, Scorpion aluminum 1.6 rockers, Comp Cams Magnum 266HR, Explorer intake, 65mm TB, MAF Conversion, 19# injectors, Ford Racing stainless P-headers, 2-1/2" cat-less exhaust w/ Flowtech Afterburner lers , SC AOD with 2800 BDR torque converter, 3.73 T-Lok rear, CHE rear control arms, full 2-1/2" frame w/1" jacking rails & seat supports, Rear disk brakes, Turbine wheels, All original interior w/ floor shift upgrade .......
Pretty much every panel on my 87 is new, rebuilt, or re constructed. :D
Join us on Facebook
http://www.facebook.com/home.php?sk=group_137541156293768&ap=1

New guy with new problem!

Reply #6 –
The A/C-Defrost door is staying in the No-Vacuum position.
With the selector in the defrost or floor position, no vacuum is sent to the A/C-Defrost vacuum motor.
With the selector in A/C you are hearing the vacuum thats supposed to go to the A/C-Defrost vacuum motor leaking.
The vacuum motor operates the door with a cable.

New guy with new problem!

Reply #7 –
Quote from: daminc;221058
Sorry, I forgot the ?
It does sound like the vac. selector. It could be why it's hissing too.

BTW.... Welcome aboard



Thanks for the comments and suggestions guys!
 I was wondering what you mean Daminc, but the missing ? sums it all up! Thanks for getting back to me and the welcome!

I'm still dont understand what is going on though with the dash vents not blowing any air, and when it is supposed to get vacume to switch the blend motor. I unplugged the vacume harness and started adding vacume to each hose seperately. I could hear the blend door moving sometimes, but all I get is the defrost or floor only.
 According to Softtouch, are you suggesting that there is a vacume leak somewhere? Or is that hissing sound normal when the controls are on A/C?
 Heres what I'm looking at. Does anyone know what color hose would operate the dash vents ???  ....





Thanks again guys!

New guy with new problem!

Reply #8 –
Quote from: 871Chevelle;221123
According to Softtouch, are you suggesting that there is a vacume leak somewhere? Or is that hissing sound normal when the controls are on A/C?
 Heres what I'm looking at. Does anyone know what color hose would operate the dash vents ???


Yes I am saying you have a vacuum leak.
I only have documentation for 84 and 87 and the color codes don't match.
Your vacuum lines go to vacuum operated motors.
The motors operate the doors in the air box.
One of the doors directs the air to either the windshield or the dash vents. When you put the selector in a position to move this door to the dash vent, you hear a vacuum leak and the door doesn't move.

New guy with new problem!

Reply #9 –
Thanks again for the reply Softtouch!
 I got the car outside on my lift checking things over for a little road trip. But as soon as I bring it back down I will pop everything apart and search around for a broken or unhooked vacume hose going to any of the vacuum operated motors.
 I know when I had it apart the first time I didnt see any motors or anything with all the clutter behind that dash! But according to you great folks it is mounted to the heater box somewhere, so I will find it!
From messing around with it, I know that the grey hose is the engine vacume, but I dont know what the other ones are either. Theres also a yellow one coming off the back of the controls that appears to drop down near the front of the center consol?
 Anyway, thanks so much and I'll post back with my results!
Joe

New guy with new problem!

Reply #10 –
I might suggest you try this question at http://www.tccoa.com they cover the mn12 cars a bit better than us.
93 Festiva L, 193k miles, BP+T/G25MR swap, T3 50trim .48/.42, SRT FMIC, Capri electronics/Rocketchip, 2.5" exhaust
bests: ET 12.86, MPH 110.25, 1.92 short
02 Subaru Impreza WRX, 129k miles
97 Subaru Impreza Outback Sport, 236k miles