Strobe Lights Setup

I don't really know much about electronics and stuff like that but I installed 3 sets of 12V Strobe Lights(from Autozone) on my truck.(2000 GMC Sierra) And they work and everything, but sometimes 2 of the sets will only have one light flashing and the other one won't do anything, it sometimes even changes from one not working to the other light. I just wanna know what is a good way to have these 3 sets of Strobe lights wired to make them work properly all the time. This is how I installed them... I have all 3 powered from the fuse box on the inside, from the fuse that controls the lights, it says "ILLUM" on it and I think it uses a 10 fuse, but I'm not sure. And from the Fuse box, each one of the 3 wires goes to it's own switch, and from there they each go to there own transformer box that came with the kit. I grounded all three right under the Dashboard to a screw that I found near the pedals. I didn't use anything else. I heard people talk about resistors and fuse blocks and all these things, but I'm not sure on what to do exactly. If anyone knows a good way to hook them up or if I installed them the wrong way, let me know. Cause it gets annoying that sometimes only one side of the strobe flashes. Any advice would be good. THANKS