Cruise control Indicator light

[homemade87]

I have a lsx 5.3 engine in a 82 that is drive by wire. I have the engine and pcm from a 2004 with the cruise control. I am trying to make a cruise indicator light come on when cruise is engaged. I cant seem to figure it out. The wire from the pcm that does this is a serial data wire. Has any one done this. The location in the cluster is where the 4wd indicator was. This needs 12volt to power up. I would appreciate any help .