I had to get to the ECUs behind the dash... it looks like death and warranty-destruction hell, but all the relevant plastic just pulls off easily after the glove-box drops out. It's all back on again now. This is pretty cheezy, minimal stuff that the dash and associated parts are constructed from. But that's how they're getting the curb weight down to 2900 pounds...
The brains. Well, *some* of the brains. It was easier to size-test pins into a more easily-accessible connector, and then dig out HV-ECU D and try inserting them for real.
I found these old connectors around the shop, the pins from which appear to be perfectly sized to go into the ECU connectors, even if they don't have the same locking tabs. First pin got sawed out of the housing, but then I found that I can just pull them out. The slight bend-up near the back is a nominal friction-fit; these are designed to be soldered into a board. Goes into the ECU connector very nicely, at least on one axis, and grabs the ECU pin perfectly. The pull-up lug retainer even lands on it firmly, so no extra strain-relief may be needed at all. Still, I companion-taped my wire to one next to it for more rigidity.
Parts for two projects at once: the EV-switch ECU connection ready to go, and the OBDII widget pretty much as it came.
There are these odd little slots through the bottom of the glove-box, and the assembled switch rig happens to fit right through so it lands IN the glove-box. [The foam liner does VERY odd things with the camera flash...]
Fed through from behind. This is totally version 0.1, just to get it working and semi-convenient for an impending road trip ... The ground wire isn't even permanent, it's a clip-lead onto the frame piece above, and it's *white* whereas the ECU lead is the black one. Well, it'll do for now.
It's not exactly nice car-hacking weather yet, so anything fancier is going to have to just wait a while.