Well, two wires are for the speed sensor and one for the clutch.

Try putting the ground off your test rig to the compressor body and hitting the clutch wire (probably blue) with 12V.

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

On the bench, the remanu'd compressor has three wires and poles at the plug (looking at the compressor from the front and left to right) red, white, black. The two wires from the clutch magnet are black. One wire is grounded to the chassis and then to the right-most pole. It is also joined with the other black wire directly from the clutch magnet. The red and the white wire go to the back of the compressor. While grounding the chassis, I applied 12v to each of the other two poles, one by one, then across both poles- no reaction from the clutch.

With the compressor that is still mounted on the car, I applied 12v directly to one of the other two poles, then across both the left and middle poles- no reaction.

I tested for 12v while the engine is running and the a/c HVAC control button depressed and at the lowest temp setting- no 12v detected.

I jumped the two leads across the low pressure sensor- no change.

Replaced OVP with a brand new one, replaced MAS with two used spares.

No Trouble codes present.

What am I missing?

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03 CLK430 Cabrio 211K Pweter Silver/ Oyster Leather
90 300SEL 214k Pearl Black/ Alto Grey/Black Leather

Prior: 85 190E, 88 300TE, 89 300TE, 90 300E 2.6, 90 300TE, 92 300E 2.6, 91 and 93 300SL, 87 Ferrari Mondial Cabrio