ok, face the front of controler(where the steering knob is) towards you and look to the right of the knob, there will be a little plate that has some numbers on it they will say something like 27.195mhz or 27.127mhz, don't take the number on the outside for as the absolute crystal number. Take a small pair of needle nose plyers or something that you can gently pull the crystal box out, now look at the side of the crystal and you will see some numbers printed in black on the side of the crystal, that is your crystal number. Now on the car open the box where the batteries are and the reciever is in side there, that's the deal that the antena is coming out of and all the servos are plugged into, check the crystal in that by pulling the crystal out with the little white tag that is connected to it, there will be a number printed on the tag it should match the crystal in the radio. If they don't match you will need to either get a new set on line or go to your Local Hobby Shop and get a new AM crystal set. If they do match try putting the crystal back in the where they belong and make sure everything is plugged in and try it again with everything apart. If it still doesn't work you will need a new radio set.