I have a 1964 Thunderbird, and I can't identify a feature. On the map light panel, there is a vacuum switch labeled "D". There are no existing vacuum lines connected to it, due to a rat infestation before I purchased it. The ports are labeled red, green, and white. There are two vacuum lines, red and yellow, that are attatched to a vacuum pot in the door. An accuating rod goes to the lock mechanism. The red and yellow vacuum lines run under the dash. I was wondering if anyone had any information about this. Thanks.