Should this part hold vacuum Euroheadlights?

[fred98050]

Hi,

I understand that the top plug is from Vacuum source and the bottom one goes to the headlights.

No matter what setting 0, 1, 2 or 3 it does not hold vacuum.

Is this normal?

Thank you.

Fred

[79Mercy]

yes, it won't hold vacuum, it just vents vacuum on 0.

[MBeige]

I have a problem with adding these to the car vacuum system. Either nipple (top or bottom) on the switch won't make the headlights work. When I apply vacuum directly to the lights, both point up...but when I apply vacuum after this switch, nothing happens.

[Sev]

Originally Posted by MBeige

I have a problem with adding these to the car vacuum system. Either nipple (top or bottom) on the switch won't make the headlights work. When I apply vacuum directly to the lights, both point up...but when I apply vacuum after this switch, nothing happens.

possibly a problem with the vacuum bladders inside the euro headlight housings. apply vacuum, and listen to the bladders. do you hear air hissing sound?

[Actros617]

Mine works, is just where you get your vacuum source, I get mine direct from the brake booster line, also you need a vacuum tank for the headlight, i am planning to use the door lock vacuum pump just for the headlight...

[fred98050]

What vacuum tank?

lost me there.

I thought that, from the switch, you have one plug for the vacuum the other goes to the headlights. Also, from the vacuum source to the switch, I have a check valve, but that's it.

I evidently need some help.

Thanks

85 300SD

[MBeige]

Originally Posted by Sev

possibly a problem with the vacuum bladders inside the euro headlight housings. apply vacuum, and listen to the bladders. do you hear air hissing sound?

Only when letting the air back in (releasing the vacuum hold). But as I directly apply vacuum to the actuators in the headlights, they hold VERY well.

As for the source I tapped the accessories line on the brake booster hose (second vacuum plug). First one is for EGR/transmission/VCV. Right after the second plug I have a 3-way connector for the Euros and the accessories main line, which divides into the 4-way connector (2 for the central locking, 1 for climate control, 1 for ignition).

I did not tap a reservoir, I don't know how that is needed but I know it's part of the diagram. So with that instead of a 3 way check valve (2 in, 1 out) I installed a one way check valve (blue/black), which was NOS part I had from years ago that I never used. Checked it prior to using and air only goes one way so I routed it properly.

Still, the headlights do not want to move when I dial the switch from 0 to 3 and/or back. Is it supposed to be instantaneous?

When I set it to 3, the engine will not shut off. If it's at 0, 1 or 2, it shuts off immediately.

My other problem is why are the lights pointing UP, instead of down? These levelers are supposed to be to illuminate the road when the rear end is sagging with weight and the front end is pointing up. Headlight beams will not be able to cover the road in front so the leveler is designed to point the lights down, correct?

[fred98050]

Originally Posted by MBeige

My other problem is why are the lights pointing UP, instead of down? These levelers are supposed to be to illuminate the road when the rear end is sagging with weight and the front end is pointing up. Headlight beams will not be able to cover the road in front so the leveler is designed to point the lights down, correct?

You are correct, the lights should point down. I saw one today and the lights move pretty fast.

[fred98050]

Originally Posted by 79Mercy

yes, it won't hold vacuum, it just vents vacuum on 0.

How about, 1,2 and 3. Should it vent vacuum as well?

[Yak]

http://www.fourbyfourclub.com/W107HeadlightsAdjustmentKit.pdf

It makes sense that with the vacuum it would be in the raised position. Standard planning is to fail/default to a safer mode, so when you lose vacuum, the headlights would tilt down and not blind other drivers.

In position 0, the switch would be a bypass to full strength vacuum to the lights and the lights would be raised (level back end)

In 1 or 2, the switch would pass a little less vacuum and the lights would be tilted down or lowered (compensate for change in angle due to lowered rear).

And in position 3, the lights would go all the way down, which would dump the vacuum. I've read, and I think I recall from my old Audi euro light days, that position 3 was only recommended when towing a trailer. If the switch is connected to your shutoff line, this makes sense that you can't shut off your car in 3. There may be another small hole on the switch that is a vent. If so, block this hole (basically defeating the purpose of the switch) and see if you can shut off your car in position 3.

Or if you've got a vacuum gauge (Mity-Vac) put the gauge where the lights would be in your vacuum circuit and measure the strength of the vacuum in each position. I'd anticipate full vacuum at 0, a little less at 1 & 2, and none at 3.

[MBeige]

Originally Posted by Yak

http://www.fourbyfourclub.com/W107HeadlightsAdjustmentKit.pdf

It makes sense that with the vacuum it would be in the raised position. Standard planning is to fail/default to a safer mode, so when you lose vacuum, the headlights would tilt down and not blind other drivers.

In position 0, the switch would be a bypass to full strength vacuum to the lights and the lights would be raised (level back end)

In 1 or 2, the switch would pass a little less vacuum and the lights would be tilted down or lowered (compensate for change in angle due to lowered rear).

And in position 3, the lights would go all the way down, which would dump the vacuum. I've read, and I think I recall from my old Audi euro light days, that position 3 was only recommended when towing a trailer. If the switch is connected to your shutoff line, this makes sense that you can't shut off your car in 3. There may be another small hole on the switch that is a vent. If so, block this hole (basically defeating the purpose of the switch) and see if you can shut off your car in position 3.

Or if you've got a vacuum gauge (Mity-Vac) put the gauge where the lights would be in your vacuum circuit and measure the strength of the vacuum in each position. I'd anticipate full vacuum at 0, a little less at 1 & 2, and none at 3.

The sad part about all this is that this is exactly how I understand it but the darn thing won't work in mine even if I set it up properly.

Now my question is that is it possible to adjust the lights so that it won't make them work? I don't want to keep adjusting the lights only to realize I got it all out of alignment again.

Yes, 0 is full vacuum as per the gauge indicates around 11-12 inches Hg. 1 less than 0 around 8-9 inches Hg, 2 even much less I think around 5-6 and position 3 is maybe 3-4 inches of Hg.

Even with all these things setup as it should be (as far as I can tell) the lights still won't move with the switch...

[Yak]

Originally Posted by MBeige

Even with all these things setup as it should be (as far as I can tell) the lights still won't move with the switch...

Have tried removing the car's vacuum supply from the process? It's possible that when everything is installed correctly due to other demands that there just isn't enough pull on the lines to move the actuators.

I've got a similar problem in my coupe with the vacuum controlled seat back locks - they only lock when I put the ACC into defrost mode because (I think) there's a minor leak somewhere on one of the flap door actuators. Similar behavior - they tested perfectly in isolation, but not when connected to everything else. I can use my ACC as a "seat lock button" - I select defrost and I can watch the pax seat actuator move. The check valve on the seat back line stops them from unlocking when not in defrost.

Try a very short test run using Mity-Vac connected to the switch then connected to the lights. It should pull the lights up and hold them in the 0 position, maybe hold them in a lower position or slowly drop them in 1 or 2 (as the vacuum 'leaks' from the switch - but you might be able to hold them up with slow pumping) and it should drop them in the 3 position. This may test your components and isolate the problem at the supply.

--Edit-- watch the pressure gauge on the Mity-Vac for bleed down. You may have to block the vent hole on the switch after changing selections, or maybe use the "brake bleed" kit as a mini reservoir so you don't immediately dump all vacuum when going from 0 to 1, 2, etc. --End edit--

If nothing else this may give you a data point of how much vacuum you need on the actuators to pull them up. Then you may need to start troubleshooting to eliminate enough leaks on your accessory line or select a supply point that consistently provides that much vacuum.

Or install everything and select defrost? It works for me!

[Yak]

Also - maybe re-look at how your check valve is installed. The check valve should create and hold a low pressure area (think vacuum reservoir) isolated from a high pressure area (vacuum leak or other user). The switch is itself a leak or user, so that may "confuse" a check valve and cause it to stop air flow and prevent any vacuum from going to the light actuators so they stay depressed.

I would think a reservoir would also be useful in the headlight set up to act as a consistent source of vacuum and be a damper to headlight "swings" due to fluctuations in vacuum supply/demand on the accessory line - like a shock absorber. This function may be served by other reservoirs in the system as long as they're on the correct side of the checkvalve.

[MBeige]

I remember checking the two inlets at the main vacuum hose to see which one generates more vacuum. It turns out the accessories line generated more, 17 in Hg compared to 16 in Hg. So I tapped into that line. I'm pretty sure all my leaks are gone because I replaced the central locking actuators and the central locking system works for many days w/o losing vacuum.

The check valve I installed allows vacuum to run towards the main vacuum hose, but prevents any leaks from moving backwards to the switch (which we both verified "bleeds" vacuum). The check valve is installed with the arrow pointing to the direction of the main vacuum hose.

What is the best way to create a reservoir?

When I connect the lights to the switch, and then the Mity Vac to the switch to simulate the car's vacuum the headlights do not move at all even if connected properly and in any setting of the switch.

[Yak]

I thought the Mity-Vac test would at least work on 0, but there may be a continous bleed from the switch that prevents the Mity-Vac from pulling enough vacuum to move the actuators. It makes sense if the switch bleeds off 5-6 in Hg even in 0 (from 17 to 11-12).

With the switch installed normally, try capping/plugging the green A/C line, then test the lights. If that doesn't work, also cap the central locks. This basically diverts all vacuum to the switch. If it doesn't work in this set up, then you may have a faulty switch.

Or - and I know it sounds silly - change the settings on your ACC. If you substitute "seat backs" for "light actuators" the same thing happens my car. I can't draw enough vacuum to move the locks, even though all components test okay in isolation. When I change the ACC setting, they move.

You might be able to "borrow" the A/C vacuum reservoir. Do you have a check valve with red/gray and green/yellow lines exiting it? The red/gray is supposed to go to your A/C reservoir inside the left front fender (behind the wheel liner). Do you have a T-connector you can install there? Hooking your lights there would add a continuous bleed to the A/C system, though.

Check here for more info: http://images.google.com/imgres?imgurl=http://i25.photobucket.com/albums/c70/cyberbach/VacuumValveSteeringLock.jpg&imgrefurl=http://www.benzworld.org/forums/w123-e-ce-d-cd-td/1456119-another-vacuum-problem-need-help-2.html&usg=__gOpju3wL66nSv1ViHsVsX6y2tas=&h=307&w=365&sz=14&hl=en&start=11&um=1&tbnid=79QetIg8ub3B4M:&tbnh=102&tbnw=121&prev=/images%3Fq%3Dmercedes%2Beuro%2Bheadlight%2Bvacuum%26hl%3Den%26rls%3Dcom.microsoft:en-us%26um%3D1


and here: http://home.comcast.net/~phantoms/vacuum/heating_ac.jpg

http://home.comcast.net/~phantoms/vacuum/heating_ac.jpg