Robert Cox
Senior Member
- Joined
- Mar 4, 2004
- Messages
- 65
- Reaction score
- 0
- Age
- 77
- Location
- Victoria, Australia
- Your Mercedes
- 2011 C200 CDI
In tracking down my vacuum leak, I used a hand vacuum pump to test the vacuum pipes on the junction box in front of the fuses under the bonnet. (1994 C180 with air con)
As far as I can tell, their destinations are...
light grey - from manifold
dark grey - to vacuum tank
burgundy - to headlight level control
white - ????
black - ????
medium green - ????
(Thought there were 7... must have forgotten one. There's also a bluey-green pipe not on the junction box, which goes to the auto trans.)
Anyway, except for the light grey (naturally) all the others hold vacuum except for the medium green one. This does hold vacuum until I turn the ignition to position 2. A buzzing sounds from the engine for a few seconds, and then it loses 75% of it's vacuum. It loses the last 25% in 2 steps a few seconds apart (with a click coming from LHS under the facia each time). My thoughts are that the green pipe goes to the heat/cooling control. I guess the leak is in either the buttons/switch controls or the actuators on one of the air flaps.
Can anyone confirm where the green pipe goes (Haynes is useless - hardly even mentions "vacuum" and I don't have access to Bentley).
Thnx.
As far as I can tell, their destinations are...
light grey - from manifold
dark grey - to vacuum tank
burgundy - to headlight level control
white - ????
black - ????
medium green - ????
(Thought there were 7... must have forgotten one. There's also a bluey-green pipe not on the junction box, which goes to the auto trans.)
Anyway, except for the light grey (naturally) all the others hold vacuum except for the medium green one. This does hold vacuum until I turn the ignition to position 2. A buzzing sounds from the engine for a few seconds, and then it loses 75% of it's vacuum. It loses the last 25% in 2 steps a few seconds apart (with a click coming from LHS under the facia each time). My thoughts are that the green pipe goes to the heat/cooling control. I guess the leak is in either the buttons/switch controls or the actuators on one of the air flaps.
Can anyone confirm where the green pipe goes (Haynes is useless - hardly even mentions "vacuum" and I don't have access to Bentley).
Thnx.
