So I ordered a set of the Recon Clearance lights (264146BK) about a year ago and have been hesitating on installing them because of the fact I have to drill through the roof and it didn't come with very good instructions or a diagram at all.

1. Make sure you have everything you need:
1.1. All the lights and wiring harness are intact and not missing or broken
1.2. 1/8” and 1/2” drill bits and drill
1.3. T-25 bit
1.4. 8mm and 10mm sockets
1.5. Center punch
1.6. Measuring tape (a fabric measuring tape is best because its flexible)
1.7. Masking or painters tape
1.8. Pencil so you can erase and move lines if needed
1.9. The screws that came with it were kind of soft and silver and I wanted black. Lowes has the following: Hillman 10x1-1/4” Black Chromate sheet metal screws. Product # 884861 and you will need 10.
1.10.The kit came with rubber washers but they can deformed once you tighten them down. Lowes has the following: Hillman Black Flat Washer #6. Product # 885806 and you will need 10 of these also.
1.11.Silicone is a MUST! Because my truck is black I used DAP Dynaflex 230 Black silicone Lowes product # 553860
2. Clean, dry and tape the front part of the roof where the lights will be installed
3. Measure up 4” from the front edge of the roof and make a continuous line following the curve of metal all the way to the other side. (see pictures)
4. Do the same at 6”
5. Refer to the pictures below for the layout I used. You can change any measurements if you would like but these provided will get you five lights that have an equal distance between each. Some people like putting the three center lights closer together than the two outside but I really think that looks off.
6. The following are for a 4thGen 2014 Mega cab with a sunroof. Likely if you are close to this model the measurements will be the same but please check very carefully before drilling.
7. The far left and right lights need to be set back from the front of the roof at the 6” mark because of the curvature of the roof.
8. The three center lights will be placed at the 4” mark from the front of the roof.
9. From the left and right edge of the roof the left and right lights are set at 5 3/8” to the center of the light and 4 5/8” to the rear hole.
10.The center light was 26 ¾” from the left or right to the front center of the light. The back was 26” from left or right to the center.
11.Each light on the left and right of center light was 10 11/16” to the center light or the left or right lights center point. This gives you the equal spacing.
12.It is best once you get the measured points laid out to draw a straight line front to back for each light. This makes it much easier once you are ready to use the center punch.
13.Once you have everything laid out its time to check it 126 times to make sure its correct LOL
14.Time to lower the headliner, fairly easy. You will need a 10mm for the front grab handles and a 8mm for the sun visors and a T-25 for the sun visor catches.
15.I didn’t take anything else loose because that was enough room to gain access to the wiring.
16.Also check underneath the headliner to make sure you aren’t going to hit any wires. I had to disconnect the left side GPS antenna wire because one hole would be close to it. It goes back in the same place after the drilling is done.
17.Align each light with its respective layout marks and use a center punch to mark it location
18.Measure back 2” from the front of each mounting screw to establish the wiring location. Center punch this location as well.
19.Use a 1/8” drill bit for all 15 holes. The two screw holes for each light and the wiring hole as a guide for the larger ½” bit.
20.Swap to the ½” bit and drill the 5 wiring holes.
21.Remove the tape and any metal shavings. Make sure the surface is very clean.
22.Place each light in its location and connect the wiring and verify they all are plugged in correctly. Some trucks have a wiring harness for the factory clearance lights but mine did not for some reason so I ran the power wire to the driver side to connect to the clearance light output at the fuse box F79 location.
23.Place a good bead of the silicone on the bottom of the light
24.Take your time when tightening the screws because they can strip and will if you are using a drill and going too fast.
25.That’s pretty much it..