From the coil table:
Backbox insert #1 white/grn is turned on by Q16
Backbox insert #2 white/vio is turned on by Q12

Page 3-10 in the manual is a block diagram of the GI circuit operation. You have one working, so you should be able to do comparison measurements between the two to find out where the problem is. I'm thinking the likely cause here is a failed triac driver@Q16, if the 7V (6.3VAC) is making it all the way to the driver board connector.

"When point A is low, points B & C are toggled high, this turns on the triac and the desired string of GI lights"