OK, I've thought this through and I think I understand how it should work. See if this is right. Remember this is a 68 which is a little different than a 69 but not much.
With engine running vacuum goes from manifold to tank then from the tank via the yellow hose to the middle relay bib. A Tee in that yellow hose sends vacuum via a solid black hose to the headlight switch. With the headlight switch off the vacuum continues back to the top of the relay valve via red or pink hose. The purpose of the vacuum to the top of the relay valve is to hold the plunger inside the valve up which cuts off the top bib and opens up the bottom bib allowing the vacuum from the middle yellow bib to go to the bottom bib which should be green hose to the back of the actuators which causes them to retract the plunger in the actrivator which causes the doors to be closed.
When the headlights are turned on the vacuum is cut off and does not come to the top of the relay thus allowing the spring on the plunger inside the relay to push the plunger down which cuts off vacuum to the bottom bib and allows it to go from the yellow middle bib to the top bib which should be red hose and go to the front of the actuators thus causing them to extend the plunger out causing the doors to open.
When you activate the override it pushes the plunger in the relay down manually thus emulating the headlight switch being turned on. So it sounds like my problem is that plunger is stuck in the down or open position. So I will suggest taking the relay off and turning it upside down and spraying WD40 on the plunger and working it in and out until it moves freely. (base on another thread I read here).
Do I got it?
If you read this before I editted it, I had everything reversed. This now matches this:
http://www.camaros.net/techref/articles/ftecref001.html
apparently the doors get closed when the actuators retract the plunger which seems kinda backwards.