Good news for your late baywindow heater problem. BBT brings brand new ventilator engines, that blow the air through your heater boxes (and fuel heater if you have that). These are brand new ventilators that are working perfectly. Tested and approved by a select group of BBT customers with only positive results! Go for that cozy heat and replace now that worn out or missing ventilator motor. They fit all buses with Type 4 engines. Fit also for VW 411 & 412 and for VW Porsche 914.