On a single-replicaset environment with a MongoS, all servers (mongoD, mongoS and 3 config servers) are configured as Windows services. All services have recovery actions that should cause Windows to restart the services 10 seconds later. Following command is used to specify the recovery action:

sc failure <mongod/mongos/mongodbconfigX> reset= 0 actions= restart/10000/restart/10000/restart/10000

If all 3 config servers are stopped and the a MongoS is started, MongoS exits (expected), however it does not automatically restart after 10 seconds as specified in the above mentioned service configuration command.

Following is the output of the sc query mongos:

SERVICE_NAME: mongos
        TYPE               : 10  WIN32_OWN_PROCESS
        STATE              : 1  STOPPED
        WIN32_EXIT_CODE    : 1066  (0x42a)
        SERVICE_EXIT_CODE  : 5  (0x5)
        CHECKPOINT         : 0x0
        WAIT_HINT          : 0x0

The suspicion is that the Windows doesn't restart MongoS that was exited with a state STOPPED instead of PAUSED.