Steering problems
 

I have a tower terror nitro monster truck that freaked out on me today after running it for around 20 minutes today.the steering went out on me.before I start up the rc truck I check to make sure the throttle and steering is working usually and when I checked it the throttle will work but the steering wont.its the same when I have the truck started up.iv read a forum on the servo being scrap in this model but that's bout it so my question is could the problem be the servo and does the servo control the steering and if so what would be a good servo that will work on my tower terror truck.thanks for any help.im new to RC driving so I'm not sure what the deal is and I dont want to get to taking it apart till I no what's going on