Alright so I know there are already a couple threads/builds that have explained how to remove the front bumped on 2015+ Colorado.
I thought some would like a detailed step by step with pics.
I removed my bumper to install some aftermarket fog lights, which you don't necessarily have to do but I was also going to paint the grill and some other stuff so made more sense to remove the bumper.
You can also follow this to have access to all the hardware on the air dam. You could then take it off or switch the clips for easy access from below for quick take off/on.
What you will need:
T-15 torx bit (shorter the better)
A ratchet to fit said bit (I used a small 1/4in ratchet)
7mm socket (again 1/4in drive)
10mm socket (1/4 drive or adapter needed)
6+in extension for ratchet
A flat head or something for fog light covers
Something soft to lay the bumper on
It also goes to say, you can follow how I did it or improvise yourself as needed and I am not liable for you messing anything up or breaking anything. Be smart.
I completed this on the ground without lifting the truck or turning the wheels. With a small ratchet and bit it's completely doable but if you can't fit between wheel well and tire you made need to turn wheel or lift front as necessary to access underneath.
Remove the T-15 screws around the top of the grill, there are 6 of them (red circles)
Remove the T-15 screws from the fender liner. I removed all the bottom and up to the 3rd one up where the fender meets the bumper. In total there are 6 T-15 and 1 7mm per side.
T-15 are red circles and arrow towards remaining. The 7mm bolt is just beyond the last T-15 towards the engine, past the liner. Will point out in later pictures. Repeat for other side
Move aside the fender liner to access the 3 7mm bolts under the headlight. It's kind of tight and annoying to reach the last one. A small ratchet and socket are handy for this. Yellow circles are where the bolts are, can see the remaining furthest and tightest in picture. Yellow arrows point to the 2 plastic clips that align the bumper, be careful not to break when taking the bumper off.
Note in green below is the fog light area. You could reach it at this point only following step 2.
Repeat for other side
Remove 2 10mm bolts from center grill. They're hard to spot initially but on the bottom grill near the center there is an angled hole to reach. This is where you will use the ratchet extension.
Yellow arrow and circles points to the holes and can see the extension hanging where to access. Repeat on other side
(yes i removed the cardboard piece that somehow lodged up in there)
Remove 4 T-15 bolts underneath
They're towards the center from where the bumper curves on either side.
Some may have problems getting to on the ground, may need to jack up as needed. Remember to jack safely and use jack stands.
Yellow circle is the T-15, note the red circles are the screws and clips that hold on the air dam
continued in next post.