Mercedes-Benz Forum banner

1 - 10 of 10 Posts

·
Registered
1991 Mercedes 190E 1.8L
Joined
·
25 Posts
Discussion Starter #1
Recently I've been replacing the ICV/Breather hoses to get rid of some vacuum leaks but I noticed one ongoing hissing near the headlight switch, particularly the adjustment switch, looks like this but adjuster is on left (RH side drive, Aus model)



I noticed the switch didnt work when adjusting lights, no change. I justified it with its old age and left it, but the hissing vacuum leak got me worried, and annoyed. I began my attempt at diagnosis.

I unscrewed the cover under the steering wheel and took a peak behind to where the switch is, everything seems to be connected fine.

I looked at the vacuum lines to the headlights, and they seem to be connected fine too. I tried tracing the paths of the vacuum lines (purple colour) but got lost into the tonnes of other cables/vacuum lines around.

I'm still trying to research this but cannot seem to find much information regarding the diagnosis of it. How do I repair this?
Any help is appreciated, thanks.
 

·
Registered
1984 190D 2.2
Joined
·
2,458 Posts
Try replacing the vacuum line first. They become brittle with age, and are a normal item to replace. A pretty inexpensive fix that will result in less problems later on.
 

·
Registered
1991 Mercedes 190E 1.8L
Joined
·
25 Posts
Discussion Starter #3
Try replacing the vacuum line first. They become brittle with age, and are a normal item to replace. A pretty inexpensive fix that will result in less problems later on.
How do I actually do that? Coz I can see the purple/yellow line and follow along until it gets crammed under lots of other cables/lines in very tight spaces.

I'd imagine replacing the vacuum lines would require removal of some stuff and other brittle lines that might crack/break.

How should I go about this step by step if possible?
 

·
Registered
Joined
·
52 Posts
You need to ensure the head light adjuster switch isn't leaking or the two small rubber hoses that attached to the switch from the vacuum lines aren't cracked or split.

Firstly remove the switch from its socket. This is done by Getting small flat screw driver and Slowly pry it out at the top and bottom edges of the switch. Once it starts to come out you can slowly extract the unit with your fingers and the two vacuum line will come out with it. Start your engine and check everything including the switch. Also ensure that the vacuum supply line is fitted to the TOP position of the switch and the bottom line goes to the headlights.

Its a very easy job to do.
 

·
Registered
1991 Mercedes 190E 1.8L
Joined
·
25 Posts
Discussion Starter #5
You need to ensure the head light adjuster switch isn't leaking or the two small rubber hoses that attached to the switch from the vacuum lines aren't cracked or split.

Firstly remove the switch from its socket. This is done by Getting small flat screw driver and Slowly pry it out at the top and bottom edges of the switch. Once it starts to come out you can slowly extract the unit with your fingers and the two vacuum line will come out with it. Start your engine and check everything including the switch. Also ensure that the vacuum supply line is fitted to the TOP position of the switch and the bottom line goes to the headlights.

Its a very easy job to do.
I tried prying it out the other but it felt like it was about to snap and break into pieces. I will try again now and report back
 

·
Registered
1991 Mercedes 190E 1.8L
Joined
·
25 Posts
Discussion Starter #7
You may need to get two screw drivers (one to the top and to the bottom) to get it out evenly and squarely.
This is how far I got... just realised its just the cover -.-

http://i.imgur.com/TLEiK.jpg

I tried using 2 screwdrivers but it feels like its going to break and I don't wanna be doing that.

Should I keep going til it finally comes out or what? seems impossible to take it out easily
 

·
Registered
Joined
·
52 Posts
If your worried about breaking it then try this.

Get a pair of large pliers and pull the big round head light switch off. The one with the small orange light on it. Once you've pulled it off remove the switch retaining nut off and the headlight panel will come away with the headlight adjuster attached. Inspect everything from there.
 

·
Registered
Mercedes 190D 2,0
Joined
·
2 Posts
If You removed cover under the steering wheel, than You can approach to vacuum switch from behind, and when You unplug hoses, just push with finger from up and bottom of the vacuum swtitch, and push the switch out. (There are some switches that come out when pushed to wards engine, bat rare). There is also optic cable that gives light to switch and is plugged to switch.
One vacuum line is comming to switch from the place just below the hood, beside fuses box (I just realized that Your's 190 is with wheel on the right so I am not sure is the splitter for vacuum hoses that go into the cockpit on left or on the right) From splitter, air is comming to switch (it is one of two that don't have valve after the rubber splitter The one with valve is for heating, and the other is for turning the ignition off (for diesel))-.
The hose that is comming out of switch is going back to engine, and towards one of the headlights, and from that headlight is going to another headlight.
And, pay attention, it does matter what hose is up or down on the switch for headlights.
 

·
Premium Member
W-1-2-3 Go!
Joined
·
16,161 Posts
On my 190E's vacuum adjuster, the "3" leaks (hisses) vacuum. 0, 1 and 2 do not. I never determined whether this is supposed to be or not, but if not then the switch itself is suspect. Headlight beams work as designed, even in "3" when the hissing sound is observed.

I've adjusted my lights a bit differently, so that 0 actually points slightly up to see further down the road, and 1 is my standard "level" beam.
 
1 - 10 of 10 Posts
Top