If you can document what was fixed with the AC to us here that could be helpful is seeing if there is a correlation. There are many knowledge people here who can help. For example Pizzaguy is just brilliant at explaining systems.

There is another vacuum line that runs under the battery too. The HVAC module has two *****. The fan speed **** controls power to the fan and that has been known to fail including the fan resister. The second **** has a mechanical linkage to a valve that controls the damper flaps.