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Originally, I had intended to do this project on my motorhome's awning. However, I sold the motorhome and bought a fifth wheel before I could do it. And since my fifth wheel already has a LED strip under the awning, I decided to install a LED strip under the "nose" of the fifth wheel.
For this project, I decided that I needed both a blue and white light. The blue light, being less intense, would work great for a night-time light, yet not be so bright that it annoys the neighbors. And the white light would be helpful in providing additional light should I need to hitch the unit up at night. There is already a light on the nose for doing this, but it is forward facing, and while helpful in seeing the hitch ahead of you, it doesn't illuminate the area immediately below the pin box very well.
So how do I get a combo white/blue light? Simple, use a RGB light strip... illuminate only the Blue LEDs when I want a Blue light, and illuminate all three strings (Red, Green, Blue) when I want white. So how do you do that? I am going to use a single-pole/double-throw (SPDT) toggle switch with a center-off position. In one position, I get White light, in the other position, Blue, and in the center position will be off.
Here is how I will wire the switch:
 Primary Color Connection
The diode across the switch (D1) allows current to flow in one direction but not the other. You can think of it as a 1 way valve. When the switch is in the "White" position, current flows through all three LEDs (Red, Green, and Blue), which creates white. The Blue LED is powered through the diode (D1) which is "forward-biased". When the switch is in the "Blue" position, the current flows through the Blue LED only, and the diode (D1) is now "reverse-biased" and blocks any current flow through the Red and Green LEDs. Pretty neat, huh? The diode is just a general purpose power diode that can handle at least 3Amps.
But what if I want a different color combination? Different colors are possible, depending on what combination of LEDs you illuminate. To understand this - you should have a basic grasp of Primary Colors - or specifically - transmitted Primary Colors, which are Red, Green, and Blue.
Primary colors allow you to create virtually any other color using any combination of two primary colors (if you use all three primary colors, you will create white). So using specific combinations of Red, Green, and Blue, we can create three new colors; Yellow (Red+Green), Cyan (Green+Blue), or Magenta (Red+Blue). And by using different intensities of the three primary colors, we can create virtually any other color. As well, different LEDs will produce slightly different colors. This may result in Red+Green producing Orange instead of Yellow. You will simply have to experiment with the color combinations. You could dynamically mix the different colors with a variable resistor in series with each LED, however, this can quickly become complicated as it would require a large wattage resistor, and a more efficient circuit would be to control the intensity via MosFET circuit. I have not gone to this level of sophistication as it is not needed in my application. However, there are many circuit descriptions on the internet that will show you how to connect such a circuit.
Wiring the LED strip for different colors is a fairly simple procedure. Compare the circuit above with the one below. The only difference is the grouping of the LEDs. Use the top circuit to illuminate any of the primary colors (Red, Green, or Blue), and use the bottom circuit to illuminate any of the secondary colors (Yellow, Cyan, or Magenta). Of course, the top circuit shows Blue, but simply select the proper LEDs that turn on. Essentially we are just re-arranging which LEDs come on when the switch is thrown.
 Secondary Color Connection
For example, if you wanted Magenta (purple), you would illuminate Red and Blue. So in the Secondary circuit, Green = X, Red = Y, and Blue = Z. This I suppose could be confusing, so you may want to re-draw the circuit with color labels to reflect which LEDs are on and off.
 Using MosFETs to create any color
The drawing above shows how a purpose-built MOSFET controller could be used to control a LED strip. Virtually any color you can imagine is possible with this setup. This particular controller can provide up to 9Amps of current, which will power two or three 5Meter LED strip. Note that this is a non-wireless controller, which sometimes has an advantage in a RV environment. There are also single channel motor speed/LED controllers available which would also work, however many of them will not work due to the common + side connection of the three LED colors. You would have to find one that supports "LOW-SIDE" connection to the LED strip.
The location for the switch will be in a small box, located in the front utility storage area of the RV. The switch box will also contain a switch for the Tire Pressure Monitoring System (TPMS) signal repeater, as that was a convenient place for both switches. I obtained those nice switch labels from Carolina Laser (www.legend-plates.com), for just a few dollars. Sometimes just a little extra touch like that makes all the difference in a project that you can be proud of. The switch panel itself is wired to a fuse panel I also installed, which allows me to add several expansion circuits in the future.
I attached the LED strips to the underside of the nose with VHB tape. I ended up peeling off the original tape that came with the LED strip and replaced it with VHB. VHB does require about 24 hours to fully adhere, and I was having some issue with gravity working against me, so I ended up having to install a couple of clips to hold the strips in place. The VHB in combination with the clips will keep the strips in place. I did not want to use the channels here as I wanted as low of a profile I could get in this area. The channels work well under an awning though as the awning itself masks the profile of the channel.
Project Video.
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