T3 A/C Install?

[Grantus]

Just re-read your post. 
Is yours a C as well?
They were the only Caravelles without air conditioning as far as I know

Pretty sure it was a dealer “tick the box”, and sent off to have it fitted locally.

I wasn’t offered AC as an option on my non aircon Caravelle CL, when buying it new in 1988. 

The auto Tassie T3 CL I bought and had here for a while, did have a non working aircon overhead aircraft style system, and the one week it did work, after $1.5k of bills, it was not very effective, as you say…….It’s a huge air volume space to cool down, as opposed to a family sedan.