I am trying help my friend work on his truck. I noticed the ACDELCO Part # 212578, something to do with Purge vacuum has a rubber elbow on it and no line is connected to it. Can someone post a pic of where the lines run? It has one line going to the vacuum canister and the other port on it is not connected to anything? Sorry for the crappy explanation, i'm at work lol.

Thanks. I will have to double check, truck is completely new to us and we looked everywhere and did not see where it would connect. No check engine codes though.

That little rubber elbow connects to nothing, are you asking about the other line parallel to the line going to the vacuum canister?

If you are asking about the other line parallel to the line going to the vacuum canister, then see the attached picture, I drew a red line where it should go to.

When you are looking at the engine, on the left of the vacuum switch thing it has the rubber elbow that a hose can connect to but the hose is missing. It should be like the pic you showed me. When i'm at home I plan on buying vacuum line and trying to fix it. Just wondering if it matters, cause the check engine light is not on.

mine is a 99 and it seems different but i have a vent on the driver side and it has a big tube that goes to the pcv and the little tube goes to the firewall on the pass side under the ac accumulator. must be a switch for the heat or something thats vacuum operated

I wish I was home already to look lol. I know the 4x4 mode won't kick in and i was told thats vacuum related. I hope the 4x4 issue would be that simple. I will try to take a picture in-case i described it wrong.

chevy, hasnt used a vacuum hub actuator in many decades if ever. this tube is for the vacuum thing that shuts off the coolant flow to the heater core if im following you