Hello, I believe I have a vacuum leak. When I accelerate, my AC air volume decreases. I think a flap is closing. The blower seems fine and I have a new alternator.

I was looking at the front of the engine under the front cap and there is a vacuum solenoid with 3 ports and electrical connector. The one pointing downward has no tube in it.

Should it? If so, where does the other end go?

Thanks

Hello and welcome to the forum! Take a look at the link below to one of our site's DIY tech articles on vacuum issues. It should help you troubleshoot. Please let us know if you have any other questions or if we can assist with any part needs in the future.

https://www.pelicanparts.com/techarticles/Mercedes-Benz/09-ENGINE-Fixing_Common_Vacuum_Leaks/09-ENGINE-Fixing_Common_Vacuum_Leaks.htm

The valve is for emissions air injection and won't affect the AC.

You need to look for a white plastic line that runs from the intake manifold , along the engine wiring harness and to the passenger side of the car. The line should end in the under hood computer box on the passenger side.

My 97 C280 with the same engine is set up like this and I think my 97 E320 parts car si the same as they share the same engine series.