I found that I have two broken HVAC vacuum control lines close to the battery. Upon further inspection, I found the line that runs through the firewall into the cabin was bundled in a wiring harness and I was able to fix that one. How does the line that runs from the vacuum tank to the manifold route? I can't seem to locate it in the main wiring harness. I can't see the back of the manifold. I would prefer to tap into the old line instead of routing all the way to the manifold. Can someone explain how the manifold HVAC vacuum line routes to the vacuum tank under the battery?

 

Below is the vacuum point on the rear part of the intake.
Big port goes to the brakebooster and the smallere port below the MAP sensor goes to the lower point under the vacuumtank shown on the last photo .

Hope this help

 

The vacuum supply tube that goes from the back of the intake to the vacuum tank at the bottom of the passenger fender runs inside a wiring harness behind the intake manifold:

 

Does the fender have to be removed to access these lines (and tank)?

 

No. You don't have to remove the fender. Take off the tire. Remove the in fender access panel. Remove the traction control module. You can then access the tank. It may actually be easier to remove the panel fender panel.


If you just have a broken line, more than likely it is broken close to the battery. You can just remove the battery and patch the line. You can patch the line with a rubber hose. The proper sized hose to fit over it is right there with the vacuum lines, connectors and caps at the auto parts store. Just snip off a piece of line and then bring it to the store and find some rubber line that fits over it snugly. Fixing the vacuum lines will cost less than $10 if you do it yourself.


BTW: I figured out the answer to my vacuum line to manifold routing question. Everything on my car is custom performance stuff. Nothing on the engine is standard except for the block. When they dropped the chassis and engine out of the bottom of the car, they cut the line and pulled it out of the wiring harness. When they put the engine and chassis back into the car, they didn't want to take the manifold back off to connect the line so they added a vacuum line that comes out of the side of the engine close to the brake booster. That port was capped and the vacuum line was never reconnected. I was able to determine the routing from the back of the manifold to the capped vacuum port with an endoscope.

 

Thanks. Because I've deleted the AIR pump, I want to disconnect the hose that leads to the AIR pump solenoid to ensure it never gets cracked/broken and leaks.

 

I had a batteryleak om my car and took these photoes when cleaned and repainted under the battery .

When you remove this cover



You will see the PCM and Tac module in front of you




If you look to the left of the PCM/TAC module , you will see the vacuumlines like this

 

Very nice and clean pictures!!! THANKS!

Bill

 

Hi i recently bought a c5 and i know this is an old thread but it saved me a lot of aggravation. thanks a bunch !!!