Diodes from Radio Shack. Part #'s 4001, 4002, 4003, or 4004. They're all basically the same and your only issue is gonna be the length. They're less than a dollar so its relatively cheap...
Everything runs from the low beam fuse. The low beam fuse has 4 pins, labeled with numbers. Take the 85 pin and run the diode with the bottle cap pointing toward the highbeam fuse 85 pin. You have to pull out the fuse and look at the numbers to make sure you're getting the right one.
After running the diode from the low to the high beam 85 pin, you now will be able to reain your low beams with the use of your highbeams.
Next, take the second diode and run it from the 85 pin of the low beam fuse and connect it to the 85 leg of the fog light fuse. You can wrap the diode around the leg itself, stick it in the hole or solder it, its up to you. Soldering it obviously is the best option since its gonna be a fail safe connection. Once they're connected to the 85 pins, you now will retain your fog lights with the use of your high beams as well.
Or....
You can take the diode and run it from the 85 pin of the highbeams and connect it to the 85 pin of the fog lights. Now you'll be able to retain your fog lights, when your low beams are on.
Some people use the DRL's as well. Some people may think that this could overload the circut. I opted not to use my DRL's because they dont put out much light anyways and I didnt want to fry anything.
This mod is for 2004 and up trucks.
I am working on some picture and i will post them soon.
Step 1. crus at it.
Step 2. get a hammer.
Step 3. torch it.