Of course it's possible.
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.
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.
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you'll just have a little
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"fun" achieving it.
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Here are some wiring diagrams.
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.
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.
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I don't know how accurate the actual electronics shown are though:
http://shinny.co.uk/toyota/MR2_SW_1993_ ... wrwind.pdf
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Don't forget that the driver's side switch has 5 positions auto-down, down, off, up and auto-up
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(the laast of which is disabled from the factory).
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I don't know if the passenger switch does, which might cause you an issue.
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Personally, if I were to do this, I would look at slaving the passenger window to the driver's window.
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A couple of SPDT relays with a couple of diodes attached to the wiring going into the controls would allow you to press the driver's side switch and get the passenger window to move in-sync.
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Of course then you ask the question of how you move the driver's side without moving the passenger side.
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.
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.
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the answer to which is the passenger window disable switch.
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