Vaccum source for heat/ac control.
 

Starting to wrap up my LQ4 swap, and one of the last small details I have overlooked is where to attach the very small hose for my heater/ac control?
This hose is really small and I'm not sure what to hook it to.
Heard there may be a tab on the stock intake I can remove and use.

Re: Vaccum source for heat/ac control.
 

I put a tee in the brake booster line at the back of the intake and ran it to the stock AC ball canister then inside to the heater/AC control

Re: Vaccum source for heat/ac control.
 

If you are using a truck intake, then there is a little tab you break off for a vacuum source. There are pics in my build thread, post 204. http://ls1tech.com/forums/conversion...c-10-a-11.html

Re: Vaccum source for heat/ac control.
 

What this guy said. Passenger side of the intake towards the rear.

Re: Vaccum source for heat/ac control.
 

It made me a little nervous to brake that off. If it brakes flush your screwed. Time for new intake. But that is a perfect place to attached that vacuum line.

Re: Vaccum source for heat/ac control.
 

Could I just cut off the tab to make sure it doesn't break off flush?
Also my climate control vacuum hose is really small. I'm worried it won't fit on that nipple.

Re: Vaccum source for heat/ac control.
 

don't see why not!

Re: Vaccum source for heat/ac control.
 

Here is the really small hose I'm talking about. Anyone know what size this is?

Re: Vaccum source for heat/ac control.
 

I just ran a new vacuum hose from the ball/vacuum canister to my vacuum source. I think I used 3/16"

Is the hose in the picture hard tubing? Or soft rubber? And where does the other end go?

Re: Vaccum source for heat/ac control.
 

Looks like the soft rubber end has broken off of your vacuum tubing (not hose). That should feed into the cab through a grommet on the passenger side of the firewall. You can get all sorts of vacuum tubing elbows and splices at the auto parts store to repair it, usually in the HELP! section. You should have a vacuum hose from the port on the intake, into a check valve, and then the check valve has two outputs, one for that vacuum tube, and one to the vacuum ball.

Re: Vaccum source for heat/ac control.
 

Hmmm, Sounds like I may have taken off more than I needed to when I pulled the motor out. Good news is I know exactly where the vaccum ball is. but have no idea where the check valve went.

Re: Vaccum source for heat/ac control.
 

The check valves are available in the HELP! section of most parts store, so no sweat there. They are only a couple bucks.

Re: Vaccum source for heat/ac control.
 

Check valve? Ok I am not sure I have one. What is the reason for a check valve on the vacuum line to the AC system?

Re: Vaccum source for heat/ac control.
 

The check valve, along with the vacuum ball, maintain vacuum for the climate control when the engine is under load (no manifold vacuum). In a nutshell, it keeps the control doors from going crazy when you mash the throttle.

Re: Vaccum source for heat/ac control.
 

Ok I got that. I thought it was already in the ball? I haven't noticed any problems but maybe that's because I have a stock lc9 motor.