There is one on the passenger side on a vent line not at the end of the line. If you add one you want to place it in front of the vac pump, it sucks towards it. Think of the hose as a straw with the vac pump being the mouth. (That sentence reminds me of a joke concerning a 50 foot garden hose and a golf ball.) ,) I digress. I put one on my 602 just in front of the pump. So far so good.

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92 300D 2.5L OM602 OBK #59