Hi guys, I'm looking for some help with an HVAC vacuum hose. After I replaced my heater hose this afternoon, I turned on the heat while idling the engine and it was blowing hot air, but only out of my defrost. I looked under the hood and I found an open-ended vacuum hose in the vicinity of where I was working and it didn't have a home. I searched everywhere from heck to breakfast in the areas where I was working and where the slack could allow it to connect, and I cannot locate where it needs to re-connect. I'm almost positive this hose is the culprit for my damper malfunction, I double checked and it pulls plenty of suction, and I have never had any issues with my Vent, Heat or Defrost controls before, so I'm pretty sure that it is whats giving my problems.

Can anybody direct me to where this ought to re-connect?

I have included a picture, but to be clear, this six-inch or so long hose connects to a tee at the other end, and one branch of that tee connects directly to the tee that comes out of the back of the air intake.

BTW, this is for my 88' 2.8L V6 MFI Camaro

Here is the pic:

 

There is a hard black plastic tubing that exits the firewall bundled into the wiring harness for the heater . Your rubber hose connects to that plastic tubing and yes most certainly that is why your defrost is always on . Look next to the heater box , toward the drivers side about 2 inches from the heater box , and you will find the wire bundle I refer to . The black plastic tubing may well be broken flush with the tape on the harness so it may be hard to spot , but it's there .

Good Luck with it .

 

Hallelujah. Didn't even think to look there. Thank you sir! Just about drove me crazy, glad I thought to ask. Happy New Year!

 

It's great when the answer is an easy one like this . In reality , the whole idea of a hard plastic tube about the size of a wire being buried in an electrical wiring harness would be the last thing most people would think to look for . Glad it you got it worked out .