Fuse diagram what wire keeps the radio's power and functions memory working

Question edited for clarity.
Question moved to model category.

There are three fuses and a relay that cover the blower. Radio probably has an inline fuse, but they are also monitored by the Body control Module.

Nissan Xterra (WD22; 1999-2004) fuses and relays

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Check the speaker wires maybe they have worked loose. And speakers themselves as they may blown. Do you have an amp if so check its fuse. Also check for inoperative interior lights, lighter, and horn. One of these circuits will power the radio's memory circuit. Some radio models will appear to work normally but have no sound if the memory fuse is blown. The clue is the clock will reset to 12:00 each time you turn on the ignition switch.

There is no Relay. But I believe that the Radio chassis has to have good ground. That can be easily checked with a test light connected to a Positive(+) Source.

As for the radio it is a power Wire that Is a constant power. This keeps the time current . If this wire is not hooked up to constant power the radio will not save the time once the car is shut off. I would also assume that the channels you try to set it to are all reset also. As this is the Power wire for memory. Not sure your brand of radio But usually all wires are marked. If not you should be able to find the Model number and look up a diagram of the wiring online.

the radios' memory wire is disconnected.. needs a constant on circuit,like the lighter socket wire, or similar..or find a power source at the fuseblock and connect to that with a 5 amp fuse in that line..

You can invest in purchasing an online repair manual for the year, make, and model of your car; or buy one at a local auto parts center like NAPA, PepBoys, Autozone - make sure it includes wiring diagrams for the fuse panel.

Has the check engine warning light illuminated on the dash? Do you have any Diagnostic Test Code faults being generated by the OBD II system?

The Ignition Off Draw (IOD) is responsible for powering the Engine Control Module or Power Control Module (or whatever name your manufacturer gives theirs), in order to maintain its memory functions. Some recommend that this fuse be removed if the vehicle is going to be sitting for any undue length of time because of the parasitic draw of the computer and the other features, like security systems and such use as well.

Vehicles have a battery drain relay that kicks in once the battery voltage drops below a certain level so that the battery is not drained completely; making a battery re-charge viable, instead of going through the expense of having to buy a new one each time something like this happens.

Each manufacturer has specific draw test procedures to perform to properly diagnose the problem down to the component level- I really don't think that having just a diagram will suffice since the tests are detailed.

I purchased the Ford Motor Company's repair manuals that the dealership mechanic's use- for my Excursion and F-250; expensive, but then again, I do a lot of my own repairs. Especially when repair shops charge over $125.00/hour for diagnostic and repair work.

You are loosing power to the keep alive memory circuit of the radio. I think you may have a defective ignition starter switch. Also there are two hot wires to the radio, one powers the radio, one holds memory and is called the Keep Alive Memory constant power wire. Here is the wiring colors, pull the radio and check the memory power supply wire.
Radio Constant (keep alive memory) 12V+ Wire: Light Green/Purple wire

TRY UNPLUGGING DIFFERENT SECTIONS OF WIRING IF THERE ARE JOINS ON THEM

your radio has been wired to the lights. you need to run a new power wire to your radio from the fuse panel using a different fuse. do you have a spare not being used? as for the volume problem, I can't help you. This should be a simple fix. if you have the owners manual, look up the fuse for the radio(look under fuses, it will have a diagram of where the fuses are and what they are) and rewire back to that fuse. hope this helps

Yes the interior lights are always hot circuits, the radio keep alive memory most likely runs off this same circuit. The fuse should be marked courtesy lights.