How to fix the dvd player on my 2004 nissan titan ?

OP Text edited for clarity and spelling

Audio Wire Color Codes for 04 nissan titan SE - Titan Talk

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2004 Nissan Titan Car Radio Wiring Chart - MODIFIEDLIFE

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Feel free to use any Nissan Titan car stereo wiring diagram that is listed on Modified Life but keep in mind that all information here is provided "as is" without any ...

No it doesn't. The head unit is faulty and requires repair/replacement.

Sounds like that the cd is jammed inside the players so you could either take the player out the dash and open it up yourself or take it to a dealership/repair shop for them to fix it for you.
Also there might be a small holes located under the cd slot big enough for a pin to release the cd manually?

you must reolace or repair the radio.

What is the model number of your unit

I changed the thermostat on mine never helped at all, then I turned my heat button to where the dot on the dial was even with the end of the red mark and I have great heat now

sounds like the switch

COULD BE EITHER CHECK THE FUSES FIRST THEN TEST THE MOTOR SWITCH SEE IF YOU GET VOLTAGE WHEN YOU PUSH THE BUTTON

do a gauge test. turn off the key and hold the trip meter reset knob. while you are holding the knob, turn the key to ACC position and hold knob for 10 seconds. this will put the cluster into self diag mode. after that happens, let go of the knob and just push it slowly / repeadly and observe the cluster assy. It should be changing and all kinds of stuff should be happening. Don't be scared, you can get out of the self diag mode simply by turning the key off again. Test gauges since those are part of the CAN cyctem also. If NG that you may need a new cluster assy.

Sounds like the head unit is bad. If the truck is under warranty , get it back to the dealership.