car will not shut off

1983 MERCEDES BENZ 300DT
200,000 MILES • 5 CYL • 2WD • AUTOMATIC
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HOUSE-TWO
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Just bought a 1983 300 tubro diesel. The car will not shut off when in the zero position. I have to go under the hood to press the off handel. Is this a swith issue/also no heat when I press the fan button no sound no heat.
Dec 23, 2010 at 4:36 PM
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FIXITMR
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the shut off is a vacuum operated switch on pump. test switch by removing line and use hose to apply mouth suction and plug with tongue. if suction holds for awhile your good. you then have to find where the vacuum leak is. hey, it could be as simple as broke/disconnected line right at pump! vacuum switch on back of ignition switch is also suspect if all else is right. do the door locks work? they are vacuum also. if there are enough OTHER leaks in system it just may be a case of insufficient vacuum to pump circuit even though it is OK.
Dec 23, 2010 at 6:39 PM
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FIXITMR
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check this page out.https://www.2carpros.com/makes/mercedes-benz/300dt
Dec 23, 2010 at 7:01 PM
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FIXITMR
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the shutoff vacuum line is the small brown hard plastic line going down behind rear of pump as you can see on that page. that page is about changing it if it is bad.
Dec 23, 2010 at 7:08 PM
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MHPAUTOS
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Did you have any luck with the suggested repairs? these vacuum systems can take some work to sort out when they start to leak.

mark (MHPAUTOS)
Jan 2, 2011 at 12:25 AM
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