It took way longer than I anticipated (for the long saga see
https://rpug.pdc.ca/index.php/topic,1626.msg11488.html#msg11488,
https://rpug.pdc.ca/index.php/topic,1626.msg11453.html#msg11453 and
https://rpug.pdc.ca/index.php/topic,1572.0.html), but I have finally got it done!
NOTE: This was done with a LM-3S. I suspect the new 21-pin LM-3S would dramatically change this install.
I've upgraded to a Scale Sound Systems speaker which works out as you have to remove most of the up-raised frame pieces holding in the factory speakers above the motors, so the LM-3S can be installed in their place. It's mounted above the 21-pin to 9 pin adapater.
For the SP Grya-lites, I had to cut the wires going from the main board to the Aux board located just behind the cab. I tagged these and tucked them in behind the main board (they are under the Keep-Alive in the photos). I then wired the green and purple wires from the 6 pin side to the Aux board for the front and rear Gyra-lites. The white wire on the 6 pin
should be able to be used for the front red emergency light, but I didn't wire it up.
NOTE: U+ on the Aux board (red wire) needs to be connected to the blue wire on the 9 pin harness.
I used a KA-2 Keep-Alive behind the speaker. I had to notch the Rapido rear light baffle to fit as it was
just rubbing when the shell was installed. You can see the notch I had to cut out. YMMV.
I did not attempt to wire up the number boards - again, I suspect this would be easily done with the 21-pin version of the LM-3S.
Finally, the Gyra-lites are controlled with the single Gyra-Lite function and a button each for the front and rear Gyra-Lites.
DO NOT use the Dual Gyra-Lite Light Effect!!