So I'm aware this how to has been done in the past, but I figured I'd make an updated 2017 version. This version also keeps stock wiring so it's plug and play! Enjoy!

BEFORE STARTING I AM NOT RESPONSIBLE FOR ANY MISTAKE AND OR DAMAGES MADE. THIS IS BEING DONE AT THE OWNERS OWN RISK. THIS IS MERELY A HOW TO.

So to get the awesome look of an LED 3rd brake light in your Cobalt or G5, you are going to need to get the actual LED strip. Luckily, it's found in a brother car to the Cobalt and it is much easier to get than in the past. You will need the LED strip out of a 2000-2004 Chevrolet Impala. Why the 00'-04' Impala? Because the board fits perfectly in the Cobalt 3rd brake light housing, and it also has all resisters built into the light board! To get one is easy. Either hop on eBay and order one (more expensive) or go to your local auto salvage yard and pick up JUST THE LED STRIP!!! It can be easily separated from the housing. After it is removed it will look like this:





After you have gotten the main piece of the puzzle, you will need the following things:

-Small gauge wire
-Wire stripper/cutter
-Wire connectors
-Lighter
-Double sided outdoor tape ($3 at Walmart)
-Soldering iron and solder
-12V light tester (not needed but helps for testing)
-Cutting knife
-Cobalt/G5 3rd brake light assembly





So first things first, remove the third brake light from your Cobalt. All you need is a 10mm to remove the two bolts holding it in place. There is also two tabs on the edge holding it to the trunk so it doesn't fall out when the bolts are removed. Be careful with these as they are very fragile. Push the tabs in gently and it should just fall out.

Next, mark which pins on the third brake light housing are your positive and negative. Flip the housing so the writing on the back of it is upright. The pin on the left is gonna be your negative, the pin on your right is your positive. Mark them with a marker. It helps:





Next, remove the black board that is clipped to the chrome housing. There are clips on each side. Pinch above them and pull it out.





Then just remove the bulbs. We won't need them anymore.





Then just remove the red lens on the housing. It has two tabs to push in on one side and it will come out. The sedan and the coupe have different lenses. Coupes being thicker and sedans being thinner.





Now here is where we need the lighter. Grab the chrome housing and go to the three holes in back. The side that has the little peg sticking out is the side we need to make a slit into for the wiring. I just used the lighter to heat up the plastic and then made slits in it with my knife. Then I took a pliers and pulled the plastic out making a nice slit. You can also use a drill but this was just as easy.





After that, grab the wire you have and cut two pieces off each about 5" or longer. Then strip each side with the wire stripper. I used black and red coated wires to easily tell which wire does what. You can use any color though.





Once you have done that, we need to lengthen the wires on the LED board so it can reach the black Cobalt board. So grab the LED strip and go to the wires on it. Cut off the metal tabs that were in the old connector for the Impala and strip those wires back. Do not strip them too far because there isn't much left. Then you can either solder the wires together or you can use connectors. In the end, you should have two ends that are still stripped, and two that are now connected to the strip:





So now you need to stick the strip to the housing. For anybody doubting the tape, I've used it in many many third brake light applications and I've never had issues. It's 3M and it is rated for 10Lbs. Anyways, stick some to each edge:







I like to do one big and then one smaller strip in the middle to accommodate the curve to make a better adhesion.

Then, feed the wires through the hole you made the slit in, and line it up in the housing. The tapering edges on the LED board meet almost perfectly with the edges on the housing, making it easy to center. Once you have it in place, press down firmly to attach it to the hosing. Should look like this now:





Here comes the only "hard" part of the whole job, and that is soldering. The way the Cobalt board is made is super simple. There is no actual wires. It's one big metal board that goes to each bulb. One side is negative, one is positive. Now go to the other side and check which pin goes to the negative part on the board and which goes to the positive. It should be that the left (negative) leads to the top and right (positive) leads to the bottom. But double check!!! The pins just lead through the plastic so it's easy to follow. Then just solder the wires to the board. Just don't burn the plastic. It helps to have a steady hand:





Once you have the wires soldered, you can start re-assembling the brake light. Once it is all together, the wires hide nicely behind the Cobalt board:





Now this is where the 12V tester comes into play. With this you can test that the light works before trying it on your car. As long as you are POSITIVE that everything is correct you shouldn't need to test it:





All that's left is to put the light back into the car and plug it in. Hit the brakes and take in the LED greatness! Hope this how to helped!