[230ina245]

Hi all,
Trying to find out where the air for the heater/fresh air system comes from.
Does anybody know the number and placement of the holes through the bulkhead that go from the area under the grill in front of the windscreen to the heater/fresh air system?
The Haynes is not very helpful here - hoping someone who has broken a 240 or at least removed the heater system may be able to help.
Tim