I have an arduino duemilanove, hc-05 Bluetooth, and a 4 channel relay module all wired up in the center of my 03' silverado and I'm using it for remote start. It works good but I have an issue with my relay module where one of the relays clicks on and off really fast multiple times completely randomly and I can't seem to figure out the problem with it. I noticed transistors or mosfets are popular for using as switches and 5 of those are smaller than the 4 relay module and I could solder them in where ever I wanted to conserve space that I don't have much of. I would also have the 5 switches that I could control individually instead of using one of the relays to give power to 2 wires at once and not having individual control. I have 2 ignition wires, 2 accessory wires, and a starter wire. I have soldered wires on them and I have my +12v wire that I use to power those 5 wires with the relays. I bought a pack of 5 rfp30n06le mosfets but I figured I would ask a simple question before I destroyed something. But it seems I should have asked before I bought them.