Vacuum pot/actuator/canister for HVAC doors

Test the diaphragm with a hand vacuum pump. If you measure a leak, before faulting the car vac pod, first verify your vac pump and hose by plugging off just the hose to see if that holds vacuum. If you get desperate, my 1985 M-B 300D uses vacuum pods in the climate box, and you can still find those in junkyards, plus likely later cars still had that. The pods are red plastic and you likely would need to mod the rods to match, plus the mounting bracket.