Complete car lighting overhaul hardware?

Hey guys, I'm looking for a little guidance on an idea. My lighting (headlights, blinkers, brake lights, internal dash and overhead) on an older truck is a little wonky, and I have been thinking about controlling the entire system with an arduino as I will have a lot more control and options. I have looked around, and found a few people who have done things like this but have gone much much more into it, like custom led scrolling lights or programmed patters, using some high end circuitry for my purposes. I want to, for now, just have the ability to control all of these functions like they would normally act. My difficulty is not the programming, but the hardware. Would the simplest method for controlling automotive 12v relays be using a transistor on all of the channels, or is there an easier method. I have not been able to find 12v relays that have a 5v control voltage, but I may not have been searching right.

Also, what do you guys think of the durability of this circuit. I am not going to be mudding or flooding my truck, but I want to make sure an idea like this would last a few years, as well as be able to operate at temperatures ranging from -20 to 130 degrees F, as the winter and summer heats could be around these at their max inside the vehicle. It may just be best to troubleshoot the wiring, but I think the ability to set up this system and program different setups would be cool (blinker and tail light flash patters, strobes, all sorts of stuff). Thanks.

In that situation I would say that an electronic control system is the wrong way to go. It ultimately relies on all the same hardware as a plain electrical system but adds in a whole lot more complexity and failure modes.

For what you want, just ensure all the light fittings and switches are in good condition (replace/refurbish as necessary) and replace the lighting loom using good quality wires and sealed connectors properly mounted and restrained.