I need to find a wire to tap that "senses the ignition switch" according to doc for the heated seats I'm installing. Can someone recommend a good place to tap into for this?

There is a separate lead that goes direct to battery/battery source, so I imagine this ignition switch lead just prevents the seats from turning on if the ignition isn't turned on.

 

assuming you need +12v when the ignition is on, there is an appropriate
connector in the under-dash fuse box:

(from the technical FAQ)

one more thing - I'd recommend adding a fuse to that wire if there isn't one
already, as the fuse leading to that terminal is 40 amps, and you can do a lot of
damage with a short before a 40 amp fuse will blow...

 

Thanks. I knew about those but for some reason I didn't think one of them was ignition