Left speaker doesnt work

Definitely need more info - such as type of amplifier or receiver, how many speakers you are running, whether the subwoofer is powered or not.
As a simple test procedure: Disconnect all speakers and plug in a pair of headphones. Get a strong audio signal? Good, move on. No signal or week signal, you have an amplifier issue before the audio even gets to the speakers.
Next: Disconnect all speakers, turn the volume down, and connect one speaker to the left output channel. Slowly increase the volume. If that works, do the same on the right channel. Everything OK? You're putting out enough gain on both channels. Sometimes one channel goes bad. You can still listen to your sound in mono moder, or drive two speakers from the single working output. Not stereo, but dual mono. Move on.
Connect left and right speakers but not the subwoofer. Repeat the test. Whatever is left is probably the problem. If the subwoofer is powered, check the power supply or incoming voltage. If the other speakers are driven off the subwoofer or powered from there, that's likely the problem.

Hi names Rui i like to help you by giving you step by step instruction in propely hocking up your logitech speakers:

Instructions

1. Connect the black plug of the rear right speaker into the black plug on the subwoofer.

2. Connect the yellow plug on the rear left speaker into the yellow input on the subwoofer.

3. Connect the red plug of the front center speaker into the red input on the subwoofer.

4. Connect the white plug of the front left speaker into the white input on the subwoofer.

5. Connect the d-sub connector plug from the front right speaker into the d-plug connector on the subwoofer.

6. Connect the green, black and orange input to the matching plugs on your computer. If you have a four-channel sound card, connect the green plug from the input audio cable to the front plug of the card and the black plug to the rear plug. Do not connect the orange input. If you are using a two-channel sound card, connect the green plug from the input audio cable to the "Line Out" jack on the sound card. Do not connect the green and orange plug.

7. Plug the subwoofer power chord into the electrical power outlet.

8. Place your subwoofer on ground around your computer desk. Position the front center speaker on top of your computer monitor.

9. Place the left and right front speakers on the sides of the monitor. Position the left and right rear speakers behind you, making sure they are pointing toward the front left and right speakers.

10. needs to support 5.1 surround. Normally, more than three sockets for sound indicates that it does. Then you need to use the software that comes with the sound hardware to configure it for 5.1 - Default will be 2.1 or just 2.
Check the control panel out. This is a lot easier under Windows 7.- Here you can access what you need via the speaker icon on the system tray (right click)
There is NO problem with your OS or hardware, this is pretty standard...

hope this will help you solve your problem.

Sort of sounds like there's a PC in the mix.

Can you swap the left and right speakers to isolate the speaker from the source as the problem?

Have you tried switching the various plugs around to isolate if anything comes out to the Left Channel, ever or if any other speaker plugged in as the Left works at all? Turn the volume down and bring it up slowly at first because if you send Subwoofer programming to a speaker not designed for it you may damage it.

If nothing works when plugged in as the Left speaker, maybe the sound card is the problem. Resubmit a question with the source or the PC as the problem

On the back of the amp, there should be a jack with the name "SUBWOOFER PRE OUT". It is a standard RCA jack, but it only puts out a line output, meaning only self-powered subwoofers will work with it. Usually, if the subwoofer does not have an amp, it will have 2 imputs and 2 outputs. You plug the two left and right inputs into the front speaker jack on the amp, and then plug the front speakers into the left and right amp on the subwoofer.

The problem is that you need the satallite speakers , they have the volume control on them which thats why you only hear the subwoofer.. yes , i tried other speakers to it and no sound either.So you will need the satellite speakers it come with.. good luck!!

No, i don't think so, but probably you audio was disconnected
Check the sound properties on control panel.
Check back connections, the power of your speakers. (bad power supply - replace)
Check your speakers on another computer

In your speaker set up you might have accidently hit the option of no sub that could be your problem Good luck

The 'Subwoofer' output on your receiver is used to connect to a powered subwoofer with a built in amplifier. Your KLH speakers use what is called a 'passive' subwoofer, it gets its power from the receiver and then passes the higher frequencies to the left and right front speakers after taking out the low frequencies for the subwoofer. A speaker system with a passive subwoofer is good for casual listening, but a powered subwoofer is required for really hearing low frequencies and rumble in movies. The KLH speakers you have were highly rated in their time for their price. The four satellite speakers and center channel speaker have very good sound compared to the little 'midget' surround sound speakers most people buy today.

Here's how you hook them up:

- The left and right front channels from your receiver terminals should go to the terminals on the subwoofer marked 'From Amplifier'
- Your left and right front speakers are then connected to the subwoofer terminals marked 'To Speakers', they do not connect directly to your receiver.
- Your center speaker is connected to your receiver terminals marked 'Center'
- Your rear speakers are connected to your receiver terminals marked 'Surround'

That should get you up and running. If the bass isn't good enough with the passive subwoofer, you can get a decent powered subwoofer like the Velodyne VX-10 for about $150 and 'kick it up a notch'. Good luck and enjoy....

You need to use a digital interface cable between the sound card and the speakers to get all of the 6 channels to work properly.

If the speaker itself is working then the problem will most likely be the connection point where the speaker plugs into. If you dont know how to check for this problem, i dont really want to tell you just in case you hurt yourself. Take it to a shop and have it looked at by someone thats knows what there looking for.