This should be my conclusions about getting my CC working.
In the end it turned out to be the TCC control. I foolishly thought that just leaving 12 volt permanently connected to the TCC. and relied on the brake TAC. connections (one with a grd till brakes are applied then 12volt.}
This would work till the ECM detected that the brakes are showing up at the TAC but not at the TCC. which through s a code that disables the CC on next keyup.
Now that the TCC is hooked up to the positive when brakes are released and nothing when there depressed. You can verify this by using the GM.STATe01-09 PID to check.