Once you have the speedo out of the cluster, you'll see the problem. The pushbutton itself slides onto the stem of the t-shaped piece which does the hard work. I can't recall the exact steps involved, but it was easy enough to replace the broken small-diameter rod with something more substantial and reinforce the potential breakage points with epoxy. I also resolved to be more deliberate with how I push the reset button, and never reset when the car is moving.
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Thank goodness we don't get all the government we pay for. -- Wiley Post