Cable coming out of that hole was originally heater control.
Someone took off the valve and shoved the end of the cable back into the hole.
Pull on it a little, one end will come out.
Well, I tried that. it wouldn't budge. So, of course I crawled under the dash, to see where it went. followed from one end to the other.
I thought I must be crazy. Traced it again.
Yep. It goes from the heater control..................................to the manual choke knob!
Pull the choke out to make the heater work! The heater control knob doesn't connect to anything.
Good thing I live in Nola and don't need a heater!