1999 B4000 wont start. Dealer indicated that transponder didnt recognize keys and reprogramed keys. Started fine for about 10 days then again would not start, different dealer reprogramed and started again for about 5 times. Back to dealer #1 and they cannot get vehicle to start even after reprogramming. They are stumped and I dont know what to do. We did install a Sirius radio but did not change any wiring & by coincidence stopped starting after Sirius sent activation signal?