AC System Problem (1996 LT4)
Thread Starter
Heel & Toe
Joined: Dec 2002
Posts: 17
Likes: 0
From: Houston Texas
AC System Problem (1996 LT4)
Face, feet, defrost or mixed, it doesn't matter. It will blow from defrost and feet all the time.
#1 - Whats the name of the piece controlling this, I thought it was called a blendor motor but I can't find info on it anywhere.
#2 - Is my diagnosis correct?
#1 - Whats the name of the piece controlling this, I thought it was called a blendor motor but I can't find info on it anywhere.
#2 - Is my diagnosis correct?
Race Director
Joined: Mar 1999
Posts: 16,950
Likes: 0
From: Stafford, Virginia Kittah, Kittah, Kittah...
Both of my 96s experienced this as well... Both times it was the A/C controller...
Any funny symptoms like buttons not lighting up when selected or no response when using them???
Any funny symptoms like buttons not lighting up when selected or no response when using them???
Burning Brakes
Joined: Oct 2002
Posts: 983
Likes: 1
From: Bergen County NJ
There are 2 control units for the HVAC system. The control head in the dash and a box (located under the dash on the driver's side) that switches the vacuum (vacuum is used to actuate the dampers that direct where the air goes) to the location that the control head is set to. Your problem could also be a simple as a break in a vacuum line.
Racer
Joined: Mar 1999
Posts: 419
Likes: 0
From: Austin Texas
My '96 CE has done the same thing for some time. It will still
switch to dash vents eventually but it's waiting longer and
longer to do it. I've read sraft's suggestions before since this
seems to be a regular problem for later model C4s. I looked
under the driver's side but like most other C4 projects finding
room to manuver hunting for this vacuum thingie is going to
be a PITA so I let it go for now. Guess I'll deal with it when
it quits switching completely.
Have a good'un................MickyD
switch to dash vents eventually but it's waiting longer and
longer to do it. I've read sraft's suggestions before since this
seems to be a regular problem for later model C4s. I looked
under the driver's side but like most other C4 projects finding
room to manuver hunting for this vacuum thingie is going to
be a PITA so I let it go for now. Guess I'll deal with it when
it quits switching completely.
Have a good'un................MickyD
Thread Starter
Heel & Toe
Joined: Dec 2002
Posts: 17
Likes: 0
From: Houston Texas
Originally Posted by wake
Both of my 96s experienced this as well... Both times it was the A/C controller...
Any funny symptoms like buttons not lighting up when selected or no response when using them???
Any funny symptoms like buttons not lighting up when selected or no response when using them???
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Doors are controlled by vacuum based on electronic signals to one of 5 solenoids. Defrost only is the default and indicates there's no vacuum. Find the source in the engine compartment and then follow it to the check valve that keeps vacuum flowing in one direction only. Usually the check valve has broken - if you can blow air through in both directions, it's bad. Replacement is about 9 bucks.
Race Director
Joined: Mar 1999
Posts: 18,226
Likes: 0
From: I live in my own little world
NC Events Coordinator
When my '94 did the EXACT same thing, it was just a plastic vacuum check valve that had cracked, and was a $5 fix! It's located under the passenger side fuel rail cover, and i'll bet'cha a donut that it's cracked. 
BUT...if you still need/want to change your A/C controler and programmer, i have one of each that i bought that i never installed.
BUT...if you still need/want to change your A/C controler and programmer, i have one of each that i bought that i never installed.
Melting Slicks
Joined: Nov 1999
Posts: 2,274
Likes: 129
From: NOVA
St. Jude Donor '05-'06-'07
Originally Posted by Alchemist
BUT...if you still need/want to change your A/C controler and programmer, i have one of each that i bought that i never installed.
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Thread Starter
Heel & Toe
Joined: Dec 2002
Posts: 17
Likes: 0
From: Houston Texas
Replaced PCV boot and check valve under passenger side fuel rail cover (which was broken). Still have the same problem.
So what am I down to that I haven't tried yet? AC controllers and some vaccume hoses?
So what am I down to that I haven't tried yet? AC controllers and some vaccume hoses?
