Do I have to program a brand new transfer case module on a 99 Yukon

Just The selector switch

FIRST > Closely inspect all related wiring for any sign of damage / chaffed insulation. This will likely be near the transfer case itself - also at the front axle actuator. Lastly > Disconnect transfer case shift motor wire connector - does fuse still blow? Beyond these suggestions - seek *hands-on* assistance from qualified personnel.

And the lights blink rapidly on the selector switch when I start it up and they go off

Okay thanks for your help