Crenwedge misunderstood.  I realize it is not the control cable.  Also, you do not have solid linkage arms as he described.  Anyway, on the tensioner, there is a flat spring and ratchet mechanism.  You can pull the idler pulley back, and the ratchet will hold it there.  You can then attach the cable, then take a screwdriver or something and pull the spring away from the ratchet notches, and the idler will shap into place to tighten the cable.  Hope this makes sense.

Problem is, if you merely replace the vacuum motor with an electric, you still need the cable system.  Do you have vehicle inspections in your state?  If not, forget the wipers and coat the windshield with RainX.

I think the adjustment is done at the Tensioner Assemblies (17590 & 17591).  Hope this helps.
Dave Dare

Have you had good luck with RainX?  I tried it but it made my windshield all "hazy" looking through the sun.  Tried to polish it out but that just took it off.  What am I doing wrong?