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10/20/2017 1:01:18 AM
9/22/2017 12:11:25 AM
Posted: 8/13/2005 5:22:22 PM EDT
[Last Edit: 8/13/2005 5:23:16 PM EDT by xanadu]
My 1996 Chev Suburban

Front and rear AC

Here's the twist...

The rear AC blows Cold and has great volume

Thr front AC blows cold, but is hardly blows at all. Head, Feet, Mix, Heat, Defrost - the VOLUME is almost nil!

The rotary fan at the passengers foot location is running strong, but the output at the vents is lacking in intensity.

I thought that there must be a blockage between the fan (above ) and the ductwork to the front of the Burb'.

Any thoughts before I tear the wrong thing apart????
Link Posted: 8/13/2005 5:23:25 PM EDT
interior air filters
Link Posted: 8/13/2005 5:24:44 PM EDT
OK, where is it?
Link Posted: 8/13/2005 5:26:22 PM EDT
You have the chevy dumb ass vacumn system that uses engine vacumn to move the "doors" First thing you need to do is check the vacumn lines to see if they are off, cracked, or otherwise defective. Crappy design, ever notice how you step on the gas and the air goes to the windshield instead of the vents in front of you?
Link Posted: 8/13/2005 5:29:26 PM EDT
[Last Edit: 8/13/2005 5:30:48 PM EDT by xanadu]

Originally Posted By fxntime:
You have the chevy dumb ass vacumn system that uses engine vacumn to move the "doors" First thing you need to do is check the vacumn lines to see if they are off, cracked, or otherwise defective. Crappy design, ever notice how you step on the gas and the air goes to the windshield instead of the vents in front of you?



I'm good , but not that good. Your saying that I need to check the vacume line conections under the hood, at the points around the engine to see it any are "open/off" or look for lines that are leaking due to cracked lines???

When the car is on the highway and I gas on it, I never notice any change in the AC voulme outbut or any change from dash to defrost.
Link Posted: 8/13/2005 5:43:16 PM EDT
look behind your ac control panel for the vac connections.then follow them from there.
Link Posted: 8/13/2005 5:53:26 PM EDT
Check vacuum lines first. Then check the fan. Two things, fan speed and blades. These trap debris which block the flow. Sometimes the plastic lining delams from the acoustic foam and will block the flow of air. If the fan speed is the problem, replace the ballast resistor if the fan only works on high speed.

The filters may not trap all dirt, this deposits on the AC evaporator core. Clean with a blast of water.
Link Posted: 8/13/2005 6:17:11 PM EDT
The fan woks on all speeds, but I'm going out tonight with the flashlight and start looking - iT'S hot!
Link Posted: 8/13/2005 6:32:40 PM EDT
OK, I've been under the dash, but the AC controls are so far up the dash that I can't see them. All vacuum lines under the hood look OK, and the fan under the parrenger foot area is clear of obstructions, and the damper works fine for Inside and outside air -

Any thoughts??
Link Posted: 8/13/2005 6:40:07 PM EDT
I had something similar (different car manufacture)and it was a bad blower control board. It controls the "amount of blow of the fan".
Link Posted: 8/13/2005 6:43:24 PM EDT
Start the engine and switch the a/c from defrost to floor to vent to face see if it changes. It should take a few seconds each time then change. You could have a blockage like foam falling apart inside the system and blocking it. You can use a air hose and blow backwards thru the vents, sometimes that will force something out.
Link Posted: 8/13/2005 6:58:29 PM EDT
I did that and the normal sequence took place.

???
Link Posted: 8/13/2005 7:00:27 PM EDT
[Last Edit: 8/13/2005 7:00:58 PM EDT by MachinegunManiac]
Remove that evil device! You're robbing your vehicle of precious horsepower! That's automotive abuse!
Link Posted: 8/13/2005 7:11:02 PM EDT

Originally Posted By MachinegunManiac:
Remove that evil device! You're robbing your vehicle of precious horsepower! That's automotive abuse!



Thanks, I'm sure that my wife and my 5 (at home) kids would agree with you.
Link Posted: 8/13/2005 7:11:49 PM EDT
But it still does not blow much? Then you have a blower fan that might have the vanes broken off. I have seen that happen. They look like hamster wheels are usually plastic and can get brittle and break, you can replace just the wheel on some and the motor and wheel on others. Have you ever heard any funny noises in the past when it was running? I'd bet that that is what it is if the rear air works fine because that uses another blower.
Link Posted: 8/13/2005 7:27:17 PM EDT
I had a 96 silverado pickup and lost the volume on the blower. The problem I had was that it sucked up a paper towel into the intake and plugged it. It was on the passenger side floor, agianst the kick pannel and up under the dash. Good luck... fullclip
Link Posted: 8/13/2005 7:31:10 PM EDT
Ok, so the damper doors and fan works fine. I am not familar with the 96 Chevy design but from the earlier designs, it is under the hood, near the right side firewall. Check if you have a filter issue. I bet you have a clogged evaporator core. Major surgery is required to gain access. Get the factory manual if you intend to DIY. Get the PROPER evaporator comb to clean the goo off the core.

This fix is well worth the PITA.
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