Testing a 300SDL electric vacuum pump

[mikeyfev1]

Is there a way to bench test a 1986 300SDL electric vacuum pump?

Please do not advise me of testing in the car; the 3 wire connector disintegrated when I removed it. I have no idea where the connections go and at the driver's door these wires are all cut. So I need to start with basic "Does this pump work?" before going further.

There has got to be a way to connect 12V to one (or more) of the 5 pins to get the pump running one direction or the other. Anyone have any help?

[arcticathlon]

Can you post a picture of your vacuum pump? I don't want to hijack the thread with something i am working on, but i have a rare 2 port w126 vacuum pump for the lumbar that i am considering swapping to a single port pump. I read that the connector on the vacuum pumps are mostly the same with my dual port pump having an extra wire for lumbar controls. I can take a picture of mine and see if we can work out the connections. Let me go outside and see what i find. I have a 91 350sdl.

[Diesel911]

I don't own an SDL but in the W123 factory service manual there is wiring diagrams. Connectors usually have a number or letter for each of the wires. That means even if the wires were gone you could look on the diagram and the number or letter and tell from the diagram what connection went where.

If there is a free online manual for you SDL perhaps someone can post the site.

[arcticathlon]

I found this:

https://www.startekinfo.com/StarTek/outside/12253/program/ETM/126from86.pdf

It is large and only works to download on Desktop, not mobile.

When downloaded go to page 112, which has the vacuum pump layout for a Year 1986.

I will post it below, but it will be better to handle the PDF, so that you can print properly.

[arcticathlon]

From this diagram, i see

Power is Red/White
Ground is Brown
Left Front Door wire is Blue
Right Front Door is Green
Trunk is Yellow
Orthopedic seats would have been Black/Yellow if you had them.

For Ground it shows a marking of 31.
For Power it shows the marking of 30.

See if you can find those on the pump to bench test.

[mikeyfev1]

Thanks for your responses; sorry for my slow response, I have to work extensively at this time of the year. I cannot repost the photos because I posted about this problem earlier, so here is a link to that article.

The part number stamped on the bottom of the pump is 000 800 05 48

[mikeyfev1]

And there are no connection markings on the pump housing at all. If you refer to that older article (where the photos are), I assume that constant 12V power should be applied across the 2 big pins used by the connector I marked as #1.

Then I assume that the other 3 pins (under round connector #2) are signaling pins; I assume that some combination of momentary power applied in one direction or another across 2 of those pins will tell the pump to run one way or the other.

A lot of assumptions on my part anyone know for sure?

[sixto]

Do you see little numbers beside the pins of the inline connector? If so, 1 is ground, 3 is +12V. A momentary +12V to any of the pins in the round connector should run the pump in pressure mode (unlock) for 30-45 seconds until it times out. A momentary ground should run the pump in vacuum mode (lock). Momentary is probably at least 3 seconds from the remote keyless entry threads. Capping the output line should cause the pump to run for only a few seconds.

If there are no markings on the pump, look at what’s left of the connector. It’s indexed to fit one way. It *will* have numbered pins.



Someone with a 126 please determine which of the inline connector pins is +12V.

Sixto
98 E320s sedan and wagon

[Frank Reiner]

Re: Post #8 (sixto)

In the flat two-pin connector, the pin closest to the three-pin connector is +12V; the other is ground.

[mikeyfev1]

Thanks for everyone's help! After much busy time (work) and procrastinating, I think I have a handle on how to test this vacuum pump.

I have attached a new photo with more labels. To test the pump, connect a ground to the pin in connector 1 marked G and connect +12V to the other pin (marked +12V).

The round connector (2) contains 3 pins, one is for the driver's front door lock, another for the passenger's front door lock and the third is for the trunk lock. I do not know which is which (no labels on the pump).

If you connect a +12V source to any of the pins in the round connector, the pump will run in vacuum mode (lock), until the pump's internal timer mechanism tells it to stop. If you connect a ground to any of these pins, the pump will run in pump mode (unlock).

After all of this, I am happy to report that my pump seems to be OK. Now I have to figure-out how to make a round connector. Mine appeared to be made of amber (translucent yellow) and crumbled into many small pieces when I unplugged it. Anyone have any ideas on how to build a connector?

[Maxbumpo]

Originally Posted by mikeyfev1

Anyone have any ideas on how to build a connector?

Coat inside of receptacle with vasoline. Push wire connectors in place. Fill in around wire connectors with JBweld, let dry. Hope and pray that the vasoline prevents the JBweld from bonding with the pump.

Maybe you can experiment with JBweld and vasoline on another test receptacle?

[sixto]

Cut the round connector off a wrecking yard 126.

Sixto
98 E320s sedan and wagon

[mikeyfev1]

Originally Posted by mikeyfev1

The round connector (2) contains 3 pins, one is for the driver's front door lock, another for the passenger's front door lock and the third is for the trunk lock. I do not know which is which (no labels on the pump).

If you connect a +12V source to any of the pins in the round connector, the pump will run in vacuum mode (lock), until the pump's internal timer mechanism tells it to stop. If you connect a ground to any of these pins, the pump will run in pump mode (unlock).

I'm going to try and build a connector, but I suddenly realized that I had another question. I can't tell from the wiring diagram, but it seems from my functional testing that it doesn't matter which wire I attach to which pin in the round connector. They all cause a vacuum draw when +12V is applied and pressure pumping when ground is supplied.

Is my assumption that it doesn't matter which wire I attach to which pin correct? If it does matter, how do I determine which wire goes to which pin?

BTW, I'm going to try and mold a connector with Phil Swift's Flex Shot that I happen to have around the house. "Like liquid rubber in a can", hehe