Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
I think the first thing to do is to examine the fuses in the vehicle's fuse box - don't remove the one for the radio for certain reasons, just examine it, with a flashlight, while it is in-place.
Then, determine the model of the JVC CD player, or at least its 'model name' if it has one on the front cover, and let me know what it is.
If it is part of an audio stack of devices, including radio or navigation or other things, then look for a way of doing a selection of 'outputs' or functions... 'Radio' vs. 'CD' or 'CD player', 'Navigation', etc. If the other device or devices in the stack is selected instead, no sound will come from the CD player in most cases.
After that... if there is still no sound at all even when volume is reasonably high on the CD player, and the CD is definitely inserted and accepted and Playing... then you should check all wiring from the speakers to the JVC devices.
In fact, select other functions/devices in the stack too, and see if you get sound from any of them. If not, the speakers (all of them?? surely not) or more likely the wiring to them, or perhaps an accessory amplifier that may be in/under the back seat of the vehicle, or else the audio amp. in the device stack in the dashboard area, may be defective.