Alex_67-327

Recently purchased a partially restored 69 coupe that came to us in many boxes. The car is a 300hp/350ci model with a TH400. The previous owner had purchased and installed a reproduction vacuum system with new hoses and actuators. Upon double-checking the routing of the vacuum lines to make sure they are correct we discovered a second T junction on the engine bay side near the vacuum canister. We've done some extensive (but clearly not exhaustive) searches here and elsewhere in order to work out where this T goes but not found anything. It is not shown in the rebuild kit instructions which we have, but because the previous owner has done such a good job in the areas he did restore, we think this T might have been there originally. This extra T fitting has a direct connection to the standard T fitting near the vacuum canister as shown in every diagram we've found. The one of the other sides of this extra T goes to an actuator; again exactly as seen in many diagrams but without a T fitting. The other outlet on this T is smaller in diameter and the smaller hose connected to it goes under the wiper/washer motor, along the firewall and through a grommet into the cabin of the car behind the heater-A/C box. Without taking the heater box out we have no idea what it connects to either. Does anyone know what this line does?

Here is a photo of the extra T fitting (circled in red) and the diagram from the reproduction vacuum system installation instructions.

Apologies if this has been discussed before but we just couldn't find that thread (if it exists).


Extra T fitting

Vacuum line diagram

Dave J

I believe the small vacuum port on the middle "T" connector connects to the hvac system, probably directly through the firewall to the console hvac selector. You are correct, most vacuum diagrams do not show this connector.

robertea

The above info is correct. The line goes to the heater/AC control in the console.

Mooser

It's called out in the HVAC vacuum diagram rather than the headlight/wiper one

M

Alex_67-327

Brilliant. Many thanks everyone for the solution and the assembly manual reference.

3X2

My 69 L71 has the same hose and T, but no air conditioning. So where does it go to?

Mooser

It's not A/C specific, it just runs the heater / astro vent controls
M