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Old 11-02-2018, 07:59 PM
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lsmalley lsmalley is online now
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Join Date: Oct 2006
Location: California
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Quote:
Originally Posted by Mxfrank View Post
Before you spend time on the speed sensor...does the A/C stay on once started? if so, then both sensors are fine.

Just so I understand...do you have continuity all the way from pin 3 on the MAS to pin 6 on the PBU? If not, the new switch may be bad, or your pressure really is low.
I connected a switch that runs 12v to the clutch to engage it on the clutch pin. The regular plug that goes to the compressor is not connected. Yes, I checked all the pins relating to the MAS which are pin 3, pin 5, pin 6, and pin 22. However pin 9 which shows a/c compressor cut in signal to (KE control unit) I did not check because I don't know what that is. So all wheres for the connector that plugs onto the compressor have continuity to their proper termination points. All wires that go to the low pressure switch have continuity to their proper termination points, and the high pressure/refrigerant temp sensor is working as it should. Whenever the pressure gets up to about 245psi - 250psi (I made a mistake previously and said a much lower number) the fan turns on and cycles off at about 180psi.
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1990 190E 3.0L
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