Hello. I’m a new member and new owner of a 81 300sd. It’s a great old classsic car but im having some issues with the climate control. So the the big thing is regardless of which button is pushed i only get air from the the defrost vents and some from the footwell area. The air is mostly cold the odd time it will be Luke warm at best. So doing some digging i may more than one issue possibly from a bad mono valve to the vacuum pods and vacuum actuators. The vacuum line that feeds the system does not have any vacuum when i have my mighty vac hooked to it. Also i have noticed that there some oily type of residue present on the hose as well as on the the row of vacuum actuator at the connectors. I hoping if some has some direction or advise in which order i should proceed with the repairs. Also if there some info ie wring or vacuum diagrams . That would be great. Thanks in advance.