First, this is not extensive - but it should help- for an electrical problem. A coolant leak is a different story, but I'll have to cover that another time. I found my aux water pump to be non-operational. Infinite resistance as measured with an ohmmeter. I made a quick test rig to put 12V to it and got nothing also. I clipped off the plugs for the aux water pump and the monovalve from my parts car. I extended one lead only on each one, so they could be attached directly from the battery to the device. Because 1 leg is short (and my SD has the battery right next to it) it's impossible to hook it up wrong. When the devices are operating properly, it's easy to both feel and hear them work.

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__________________
'82 300SD - 361K mi - "Blue"

"Good judgement comes from experience. Experience comes from bad judgement."

listen, look, .........and duck.