Vac line replace
Thread Starter
Pro
Joined: Aug 2006
Posts: 572
Likes: 57
From: East Texas
Vac line replace
Have a 96 where the AC works great but only blows on the floor. I have been told there is a vacuum line that is known to dry out and can't hold any vacuum so the dash AC controls are inoperative. Has anyone replaced this vacuum line?
Team Owner
Joined: Sep 2003
Posts: 25,360
Likes: 2,729
Yes there are 'several' vacuum lines! Is yours a C68 or C60 AC? The vacuum source from the engine passes through and is secured into the 'pass through'. That's modified by many if that were your issue.
1B-13 in the FSM has 'programmer' vacuum routing diagrams etc. Do you have the FSM?
1B-13 in the FSM has 'programmer' vacuum routing diagrams etc. Do you have the FSM?
Last edited by WVZR-1; Jul 1, 2022 at 09:21 PM.
Thread Starter
Pro
Joined: Aug 2006
Posts: 572
Likes: 57
From: East Texas
Not sure what AC I have but will look into it. The car is a 96 LT 4 if that connects any dots.
Heres what I understand. This vac hose is by design to have the AC and heat go out the floor vents if the controlling main vac line fails.
I will try and find a diagram of the vacuum lines to try and narrow the line down. My understanding is, no matter what AC the car has this line brings in the vacuum to the control unit at the dash to switch from vents on the dash, defrost and floor heat. So should the line fail the heat will go to the floor and not onto people's faces. if anyone knows about that vacuum line that supplies vacuum to the controls, I'm all ears.
Heres what I understand. This vac hose is by design to have the AC and heat go out the floor vents if the controlling main vac line fails.
I will try and find a diagram of the vacuum lines to try and narrow the line down. My understanding is, no matter what AC the car has this line brings in the vacuum to the control unit at the dash to switch from vents on the dash, defrost and floor heat. So should the line fail the heat will go to the floor and not onto people's faces. if anyone knows about that vacuum line that supplies vacuum to the controls, I'm all ears.
Drifting
Joined: Feb 2016
Posts: 1,384
Likes: 339
From: Simi Valley CA
The vacuum line that feeds the control goes through the firewall under the PB and towards the engine. I had that vacuum line issue on my 89 and it also had a poor idle. Once I fixed the vacuum line I still had issues with the AC similar to what you're saying. I had to take out the module that the vacuum line goes to and replace the resistors. They typically run too hot and burn out. I'd pull the module out and inspect it before messing with the vacuum lines. Especially if your car runs good otherwise. The module is above and to the right of the gas pedal. There was instructions on Batee's website about it too.
