One speaker works all the time the others only sometimes

Check the bal./fader on the radio sound setting there could be a misbalance in the settings.

Anything I tell you is going to be a guess, since there has been no testing done, and we don't have the model number of the specific radio involved. However...
For a 20 year old radio, the volume and balance is almost certainly controlled by a potentiometer that has input into one leg of the fixed resistance, and the other leg (of the fixed resistance) is grounded. The movable center tap is the output to the amplifier - and its position controls the volume to that channel. If the ground leg becomes disconnected (broken wire, or a cold solder joint, or even a break in the resistor within the body of the potentiometer) then instead of "dividing" the volume, it simply provides a slight resistance inline - short answer: It goes full volume.
You can try running the control full range back and forth, and even just the old time "slap it" approach, to see if you get any static or change. If you do, that pretty well confirms the diagnosis. [If not, it just means the break is not close to touching - still almost certainly the right answer though.]
Only fix is going to be disassembly. You then may be able to find the break (and resolder it), and/or replace the volume potentiometer. Note that if you have remote volume/balance control (controls on the steering wheel), then there is some extra wiring that can likewise be involved. jk

Wire come off passenger side or balance has been faded over to driver side without your knowlage

easy check to carry out ,borrow a speaker that you know works, if you remove one from another vehicle make sure ignition is off when taking speaker out, take a speaker out from your vehicle ignition off , the door speakers are usually the easiest to remove,plug in the known good speaker to your vehicle turn ignition on then radio, if you get sound then the problem is with the speakers but very unusual for all speakers to blow at the same time unless there has been a power surge through the amp. if no sound still remove radio and make sure the wire connectors are pushed home securely if they are then it's most likely the radio is not working will need replacing as a repair can be more expensive than new

Sounds like a defective radio volume control circuit.

Check the speakers if they work. Connect the speaker terminals using a short wire to a 1.5 volt battery (AA or any dry cell batter) and listen if there's a thumping sound when the wires are connected to the battery terminals. If there's no sound, your speakers are busted. If there's a sound, check if the wires are okay. Use the same method with the battery with the wires from the back of your stereo. Make a small cut on the wire and attach the short wires you used earlier.

if they are weak and crackling the weak sound might be your balance and fader .............the crackling is because the voice coil is going out another words they are pretty much junk time to replace them

check for lose wire connection off wires on solinoid and battery solinoid is connected on stater motor normally on the side off engine at the back off engine

Probably not a speaker issue. Most likely it is in the radio itself. I have found several helpful hints on-line so try to google this before going and paying anyone to do it for you.

Hi have you tried using the settings on the stereo that controls the balance from front to back and side to side if you have changed these settings without knowing then the stereo output might be in the possition for the one side.
If after doing this you still have the same problem then i would remove the stereo and check all the wires are secure if they are then you need to remove the casing for the side speakers and check the wires for corrosion and make sure connected properly.

Usually the speakers wont just suddenly stop working if the problem was with the speaker then you would have noticed over time that the sound was distorted or would have sounded crackley from the speakers.
If this is not the case then check the speaker balance on stereo and then check wires.

Let me know how you get on or if you need further assistance ok