3 red lights

There are 4 different kinds of RROD on a xbox 360. When the ring of light shows 1 red light, it means there is a minor hardware issue. If it shows 2 red lights, it means it over heated. If it shows 3, it has a major hardware failure and 4 red lights means that you dont have your A/V cables plugged in. Hope this helps.

1 red light usualy means hardware failure. There is another error code you can get of of xbox. While machine is on push the the sync button on console and while sync is pushed in press eject button. The lights on the console will give you youre first digit. Theres 4 in total. Repeat pressing the sync and eject button till you have got the four digits and console is back to the red light.
When getting codes the lights will light up. 1 red light means 1 2 means 2 and so on. 4 red lights means 0. Let us know and ill get back to you.

http://support.xbox.com/support/en/us/xbox360/hardware/default.aspx

Two red lights on your xbox mean that the xbox is overheating. Turn off the xbox and let it cool down for about an hour, maybe 2. While it is cooling down make sure that the back of the xbox is clear and has enough space for ventilation and make sure that it is clean so that air can flow properly through the system to cool it down while you're playing.

Three red lights on the ring of light is an indication of a hardware failure

Here are things to try:

1. Turn off the xbox 360, disconnect the cables wait for 20 seconds reconnect the cables and turn it back on.

2. Check the light on the power supply ( The big brick that goes to your wall )
If the light is green that means the power supply is OK
If the light is Red that means the power supply needs to be replaced

3. If above steps doesn't work, you need to contact xbox customer support to get your xbox repaired
and shipping and handling will be covered.

Follow this steps:

1. Turn off the xbox 360, disconnect the cables wait for 20 seconds reconnect the cables and turn it back on.

2. Check the light on the power supply ( The big brick that goes to your wall )
If the light is green that means the power supply is OK
If the light is Red that means the power supply needs to be replaced

3. If above steps doesn't work, you need to contact xbox customer support to get your xbox repaired
and shipping and handling will be covered.

Good Luck

it means you have a lose wire

3 Blinking red lights often means that your Xbox 360 has suffered from hardware failure.

4 Blinking red lights means that your Audio / Video cable is not correctly connected (it's the colorful one; Red, white, yellow; green, blue, red if Component)

If it IS just three lights, and you bought your xbox 360 under three years ago, call 1-800-4MY-XBOX

3 Blinking red lights often means that your Xbox 360 has suffered from hardware failure.

4 Blinking red lights means that your Audio / Video cable is not correctly connected (it's the colorful one; Red, white, yellow; green, blue, red if Component)

If it IS just three lights, and you bought your xbox 360 under three years ago, call 1-800-4MY-XBOX

ok one red light means a fault be warned this is also called the 3 rings of death if u get 2 flashes or rings it will over heat or freeze ,and if u have 3 xbox is dead ,

one means fault is it over heating,in a confined space ,

here is a site so u can see whats goin on with your xbox
http://editorials.teamxbox.com/xbox/1651/The-Red-Ring-of-Death/p1/