OK, I tinkered with the electric vacuum pump which goes in the trunk next to the spare tire well. I have determined the following for the various wires:

1. Brown is negative - goes to negative terminal

2. Red with stripe is positive - goes to positive terminal

3. The black with stripe is positive - goes to positive terminal, but it's extra since it does not need to be hooked up to anything for the pump to work

That leaves 3 wires. And this is where I become befuddled.

There's a

Green Wire
Blue Wire
Yellow Wire

I can take any one of the 3 (G, B, or Y), and depending on where the pump's polarity is, I can take the green wire, for example, and touch the positive and it blows air or it wont. If it wont, then I touch the negative terminal and it sucks air. I can then take the green wire and touch the positive terminal and it will blow air. Just depends which was touched last. You can go back and forth with the green wire, which results in a corresponding blow or suck. You can do the same exact thing with the blue or yellow wire. However, you cannot start on green, for example, and switch to blue or yellow. In otherwords, whichever of the 3 you start out with is the only one you can use to switch from blow to suck.

If you start out on suck, it will suck for around 15 seconds and automatically turnoff. OR, if you take your thumb and block the line, it shuts offs automatically also.

Here's my question: Does anyone know if there's a way to wire this pump so that is always starts and ends on suck? I have a W123 and my system only uses vacuum (suck). I want the pump to work on a simple toggle swith, turning it on and turning it off. Actually, I will be energizing the pump and the pump has an automatic shut off built inside the pump.

Any ideas?

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