Learjet 35A - Transponder does not work when starting cold

I have Flight Simulator 2020. I downloaded the Learjet 35A from the Market Place. When I start dark and cold, I cannot get the transponder to turn on. The batteries and avionics switches are on, both in the sim and on my Honeycomb Yoke. When I start the flight from the runway, the transponder is on and working. I have looked through the cockpit and made sure every switch is turned on but no transponder from dark and cold.