What's that grey wire/tube?

[Steve W]

There's a light grey wire or tube (I don't see any contacts inside the right-angle rubber boot, so I'm not convinced it's a wire) about the size of #14 wire that threads up the corner of the HVAC box under the hood and originates from inside the cab. Try as I might, I couldn't find anything within its reach that it would connect to.

Where does this go? I'll take a pic later if that would help.

Thanks, all.

Steve

 

[James86]

Sounds like a vacuum line. I have one that matches your description for my heater line valve. Its about 2-3mm in diameter and grey. There's several vacuum lines about that size along the firewall for everything from the EGR solenoid to HVAC operation.

 

[Steve W]

Thanks, James - I've suspected as much. Now I have to find out where it's supposed to connect! I have noticed erratic behavior from my heat/ac controls, so this may be the root cause.

Steve