How can you check in the junkyard if the ACCII you just found work or not?

I found one yesterday in a yard inside a 1980 300sd, it was the first time i found one without cracks.

Same question for the corresponding amplifier under the dash.

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Aquilae non capunt muscas! (Eagles don't hunt flies!)


1979 300SD Black/Black MBtex239000mi
1983 300TD euro-NA. White/Olive Cloth-MBtex 201000mi. Fleet car of the USA embassy in Morocco
1983 240D Labrador Blue/Blue MBtex 161000mi

I'll need to review the manual when I get home... but you need to apply 12V's to 2 of the pins to allow the valve to fully open with a "clunk noise" then reversing the polarity closes it, another pin put it halph way in between. I'll see if I can dig up the George Murphy document tonight.