Plug the steering servo into the throttle port on the receiver and see if the servo will operate. If it does, you'll need a new servo. If it does not, it's probably a defective receiver. Only thing is, I can not tell you that a short in the receiver will not damage the other servo. I have always done this and have not had a problem, but I think of shorts and sensitive electronics. Just want you to know my thoughts on that. I have not ever heard of it causing damage, but this is earth and anything can happen I guess. Has anyone ever had a problem with shorted receivers damaging servos? Just don't want to give anyone false instructions. How about finding voltage specs. and using a volt meter?