LR25 CREW BECAME DISABLED ON RWY WHEN NOSEWHEEL STEERING FAILED.

Narrative

ON DEC/XA/98 WE HAD A GLITCH IN OUR NOSEWHEEL STEERING AT MDW ARPT THAT REQUIRED US TO CALL THE TWR SUPVR AFTER LNDG. LNDG RWY 31C; WE HAD TFC ON FINAL BEHIND US AND TFC IN POS AND HOLD ON THE RWY. IN ATTEMPTING TO TAXI CLR OF RWY 31C AT RWY 22R; OUR NOSEWHEEL STEERING FAILED. WE CAME TO A COMPLETE STOP ON THE ACTIVE RWY; WHILE ATTEMPTING TO MAKE A NEAR 90 DEG L TURN ON RWY 22R. TRYING TO USE DIFFERENTIAL PWR AND BRAKING WAS NOT WORKING SO WE PULLED THE ACFT NOSEWHEEL STEERING CIRCUIT BREAKER AND THEN WAS ABLE TO USE DIFFERENTIAL PWR AND BRAKING TO MAKE THE TURN. IN THE SHORT TIME PERIOD WE WERE STOPPED ON THE RWY; THE COPLT THOUGHT THAT WE COULD MAKE A R TURN; WHICH HE CONVEYED TO ATC. IN REALITY; WE COULD MAKE NO TURNS. ATC MADE THE ACFT IN POS AND HOLD BEHIND US TAXI CLR OF THE RWY. WE WERE CLR OF THE ACTIVE RWY BEFORE THERE WAS A CONFLICT WITH THE LNDG TFC. WE RESET THE ACFT NOSEWHEEL STEERING CIRCUIT BREAKER AND COULD NOT DUPLICATE THE PROB. IN CONSULTING WITH MAINT AFTER LNDG; IT WAS DETERMINED THE GLITCH WAS PROBABLY DUE TO THE LARGE AMOUNT OF RAIN WE HAD FLOWN THROUGH JUST PRIOR TO LNDG; CONTAMINATING A CANNON PLUG IN THE NOSEWHEEL WELL THAT CTLS THE NOSEWHEEL STEERING. BY THE WAY; WE WERE OPERATING UNDER FAR PART 91 TO ACHIEVE A PART 135 FLT; IE; PICKING UP FREIGHT AT MDW.