Vacuum Q's
Thread Starter
Super Member
Joined: Dec 2009
Posts: 940
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From: Chapel Hill, NC/Montreal, QC
1995 C36 AMG, 1998 C43 AMG
Vacuum Q's
Hey guys, been awhile, but making the most of my Thanksgiving break by wrenching away. So far I've replaced my wiper motor, cleaned the cabin filter and a/c fan, and broken the bit that holds the spring to the car-side of the drivers mirror.
Down when I was cleaning the cabin filter, I stumbled upon the Vacuum Control Unit (takes main vacuum line from inside engine bay and uses it to connect to around 8 or so vacuum lines, that connect to the actuators for the A/C vents inside the car.) Now, since I bought it, I've had the relatively common problem that the air blows out the two side vents, and the windshield vent, and that's it. I tested the buttons and can feel the VCU actuators moving around, so I knew I had a vacuum problem somewhere. After tracing the green Main Vacuum line through the firewall into the engine compartment, I saw that it, and a light grey line both go into a hole in the passenger's side fender. Upon further inspection, the other end of the grey line was disconnected, right behind the ECU box/under the drainage system for the windshield wiper area. My question for you guys is: does anyone know where this grey line attatches? On the pre-facelift cars, a line like this went to the throttle body. Does it do the same on the 43's? I couldn't pinpoint where it was supposed to hookup, but I did seem to hear a hissing noise coming from around where I found the hose, but couldn't find anything. Could it be in the firewall?? I really don't want to have to find it from the other side (taking the dash off.) Also does anyone know where the grey and green lines go when they enter the fender?? Not sure what could be in there....
Thanks!
Down when I was cleaning the cabin filter, I stumbled upon the Vacuum Control Unit (takes main vacuum line from inside engine bay and uses it to connect to around 8 or so vacuum lines, that connect to the actuators for the A/C vents inside the car.) Now, since I bought it, I've had the relatively common problem that the air blows out the two side vents, and the windshield vent, and that's it. I tested the buttons and can feel the VCU actuators moving around, so I knew I had a vacuum problem somewhere. After tracing the green Main Vacuum line through the firewall into the engine compartment, I saw that it, and a light grey line both go into a hole in the passenger's side fender. Upon further inspection, the other end of the grey line was disconnected, right behind the ECU box/under the drainage system for the windshield wiper area. My question for you guys is: does anyone know where this grey line attatches? On the pre-facelift cars, a line like this went to the throttle body. Does it do the same on the 43's? I couldn't pinpoint where it was supposed to hookup, but I did seem to hear a hissing noise coming from around where I found the hose, but couldn't find anything. Could it be in the firewall?? I really don't want to have to find it from the other side (taking the dash off.) Also does anyone know where the grey and green lines go when they enter the fender?? Not sure what could be in there....
Thanks!
Thread Starter
Super Member
Joined: Dec 2009
Posts: 940
Likes: 0
From: Chapel Hill, NC/Montreal, QC
1995 C36 AMG, 1998 C43 AMG
Hey guys, been awhile, but making the most of my Thanksgiving break by wrenching away. So far I've replaced my wiper motor, cleaned the cabin filter and a/c fan, and broken the bit that holds the spring to the car-side of the drivers mirror.
Down when I was cleaning the cabin filter, I stumbled upon the Vacuum Control Unit (takes main vacuum line from inside engine bay and uses it to connect to around 8 or so vacuum lines, that connect to the actuators for the A/C vents inside the car.) Now, since I bought it, I've had the relatively common problem that the air blows out the two side vents, and the windshield vent, and that's it. I tested the buttons and can feel the VCU actuators moving around, so I knew I had a vacuum problem somewhere. After tracing the green Main Vacuum line through the firewall into the engine compartment, I saw that it, and a light grey line both go into a hole in the passenger's side fender. Upon further inspection, the other end of the grey line was disconnected, right behind the ECU box/under the drainage system for the windshield wiper area. My question for you guys is: does anyone know where this grey line attatches? On the pre-facelift cars, a line like this went to the throttle body. Does it do the same on the 43's? I couldn't pinpoint where it was supposed to hookup, but I did seem to hear a hissing noise coming from around where I found the hose, but couldn't find anything. Could it be in the firewall?? I really don't want to have to find it from the other side (taking the dash off.) Also does anyone know where the grey and green lines go when they enter the fender?? Not sure what could be in there....
Thanks!
Down when I was cleaning the cabin filter, I stumbled upon the Vacuum Control Unit (takes main vacuum line from inside engine bay and uses it to connect to around 8 or so vacuum lines, that connect to the actuators for the A/C vents inside the car.) Now, since I bought it, I've had the relatively common problem that the air blows out the two side vents, and the windshield vent, and that's it. I tested the buttons and can feel the VCU actuators moving around, so I knew I had a vacuum problem somewhere. After tracing the green Main Vacuum line through the firewall into the engine compartment, I saw that it, and a light grey line both go into a hole in the passenger's side fender. Upon further inspection, the other end of the grey line was disconnected, right behind the ECU box/under the drainage system for the windshield wiper area. My question for you guys is: does anyone know where this grey line attatches? On the pre-facelift cars, a line like this went to the throttle body. Does it do the same on the 43's? I couldn't pinpoint where it was supposed to hookup, but I did seem to hear a hissing noise coming from around where I found the hose, but couldn't find anything. Could it be in the firewall?? I really don't want to have to find it from the other side (taking the dash off.) Also does anyone know where the grey and green lines go when they enter the fender?? Not sure what could be in there....
Thanks!
