Many of us who are re-thinking the same thing as you are using relays. I have 5 or 6 on my Carolines truck. They are simple to use and you control them by a lower amperage wire to the cab & or IGN. switch. The higher amp. to the feature (horn, fan motors, headlights -- use two relays for hi & lo, heater motors, anything) you wish to power is completed by the relay suppling voltage to it from your stock switches inside the cab and using larger sized wires (when needed). Relays can be used as "remote control switches." It takes only a tiny amount of current to turn the relay ON. But when switched ON, the relay delivers power directly to the accessory. ("high gain" operation).
see mad electric :::
http://www.madelectrical.com/electricaltech/brighter-headlights.shtmlhere is a small sized panel that you can fit just about anywhere & can handle up to 8 features.
this one has 12 circuits
http://www.centechwire.com/catalog/panels/pdp3.shtmlhttp://www.centechwire.com/marketing/spotlight.html
