[ls1nova71]

Is your PCM and TAC somewhere where you can easily remove the plugs to check for power? If so, what I would do is remove the blue PCM connector and physically check for power at the purple wire on pin 33. With the key on, check to make sure its getting power, you can use a test light since its just power from a switch, then have someone press the brake pedal and it should go off. Then check pin 6, light blue wire on the TAC plug and it should be the opposite, no light until the pedal is depressed. This is a really quick and easy test, provided you can get to the connectors.

I have also seen on several occasions cruise not working just because the switch is a little out of adjustment, so might try adjusting the switch, usually in, so that it takes a little more pedal travel for the brake lights to come on.