I brought a 93 cd for my 99 disco and it works but it won't play it just show cd number no sound

 

Did you get a CD player for a DI or a DII?
DI and DII's both cover 1999 model year.

 

It came out a d1 and mine is d1

 

Ok, just wanted to make sure.
Sounds like your AMP is dead, happened to me so I went to Best Buy and had them install a Kenwood CD headunit.
Make sure that all of your volume buttons are turned up, the one on the dash cowl and the stereo itself.

 

K how do u disarm alarm so I can change it and thank spike

 

What do you mean?

 

i think he means he trips the alarm when removing the radio

 

Before you get into that, Make sure your CD's are the right way. They go in backwards from what you would think. Read the magazine closely.

If your radio works and the CD has no sound, it is not your amp. Do not mess with your deck. If you don't have the code for the radio, take your truck to the dealer and have them look it up for you.

 

K I have the code for the radio that aint problem but I try to flip the cds and I get a error

 

if your old cd changer did the same thing as your new cd changer then it sounds to me like there is a problem in the head unit itself or the din cable, I agree with OKdiscoguy about hearing radio and not cds you could have a pinched din cable that has broken wires in it (this is what I would check first as it will be the cheapest and may be easily repaired yourself). If that is ok it could be an internal problem on the head unit, in which case I would agree that not only will aftermarket be cheaper but you will also get better sound quality. let me know if you need any help wiring a new radio or anything else.