Don - I didn't see it in the vacuum diagram or on the wiring diagram for your car but the manuals weren't very complete for those years. There does appear to have been an air pump. possibly yours was removed. My '81 has a electrically controlled vacuum valve (Switchover valve) that controls the air pump valve. That may be what it is.
Barry -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of OK Don Sent: Saturday, May 13, 2006 7:32 PM To: Mercedes Discussion List; SL Discussion List Subject: [MBZ] Un-known device in '78 450SLC I found what appears to be a vacuum operated switch under the coolant resevoir when I removed it. It has two vacuum lines connections and a connector with two wires going to it. The wires were connected, but there were no vacuum lines connected, so I have no idea what's supposed to be sucking or blowing there -- Anyone know what this thing is for, and what vacuum lines are supposed to be attached to it? Thanks - PS - Is there a vacuum line diagram on the CD for the engine compartment?
