Hiss Noise when engine on & not pressing accelerator

[hmeah]

I just bought a 1994 C200 elegance, its had 1 owner, 34k & full Mercedes history.. i noticed that when i am driving & stop at traffic or junction.. there is a slight hiss noise coming from the right hand side of the dashboard... somewhere from where the light switch is... can you tell me if this is normal or could there be something wrong?

please help as its doing me head in!

 

[andy_k]

check the vacuum pipes connected to the headlamp level adjustment switch.

these are just where you say and will cause the hissing you describe if one has become disconnected or damaged.

HTH

Andy

 

[stwat]

I had this very same problem and it ended up being a missing rubber connector to one of the headlamps itself. I replaced the connector and the hiss disappeared from the switch completely!! The problem i now have is that when i rev the engine, the headlights dip??????? Very odd and if anyone can shed some light on this problem id be very grateful.

Stu

 

[tom7035]

Did you adjust the headlights at all when the vacuum pipe was disconnected?
To adjust correctly the beam adjuster should be set to '0' and with the engine RUNNING.