Managed to get round to tinker with it and I have a couple of questions.

1) There are 2 vacuum units, one top of the thermostat housing and the other on the engine block, next to the temperature sensor. What are they? Can I do without one or both of them? I broke the one on the engine block. It is a PITA to get to and replace.

2) It uses a electric clutch fan. How can I test it? Is there any sensor I can jumper to turn it on?

Any info is appreciated.

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Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed.

W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html

1 X 2006 CDI
1 x 87 300SDL
1 x 87 300D
1 x 87 300TDT wagon
1 x 83 300D
1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry.

Anyone?

May be I have not made myself very clear in the OP. I do not know what is the vacuum switches ( sensors ?? ) on top of the thermostat housing and in the engine block are for. They are connected together using vacuum hoses. I will take some pictures and post them.

Thanks

__________________
Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed.

W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html

1 X 2006 CDI
1 x 87 300SDL
1 x 87 300D
1 x 87 300TDT wagon
1 x 83 300D
1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry.

I'f one of them has a line going to the vacuum pump then its probably for raising the cars idle speed when the engine is cold. I have one on my N/A OM602. Not sure about the other as I only have one, sorry.

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1991 W124 250D - 130k Miles