Quote
Should I jumper TACHSELECT to XG1?

Yes, this needs to be done.
You can try using existing 390 ohm R12 from the +5V, it will pass a bit more current but to make the next step to get it fired up.
Then change it out later to lower the current flow.

If that saves a trip into town.

Cheers, Charlie
If It ain't broke, Modify it!
87 Montero turbo Converted back in Spring1989
95 Montero SR 3.8 DOHC Only one?
93 Pajero 3 door 6G75 Mivec with paddle shifted 5 speed
Then a Gen2 SR with full coil independent suspension.