problem with air condition ducts
 

hello.. i have a 95 w140 600.. the best car i ever had by far.

ok.. there is a problem with the air blowing from the ducts. Whenever I accelerate the air is directed to the windshield.

the higher the economy gauge goes the more the air is directed to the windshield..the lower it goes the more the air come out the front ducts.

I am assuming here the problem is related to some vacuum line, i imagine that when more vacuum is generated in the engine , some vacuum line "suck" the "duct flap" which leads the air to to the windshield. :confused:

I live in an area where temperature is 47 c . So this is inconvenient for me.

Thank you.

Sounds like you have a vacuum related issue. Get a tool called a Mighty Vac and a vacuum line routing diagram and start checking for leaks.

Vacuum is your problem.

The system is equipped with reservoir(s) that allow vacuum to remain on the various flaps while you accelerate (low or no vacuum condition).

Your problem is a classic example of a vacuum leak in the system.

I would expect your car to be rather complex, so an accurate schematic of the vacuum system is required to troubleshoot. It can be tedious, but it is not rocket science, so it's doable by anyone with light duty or better skillset.

Jim