Stian, Out of all the relay's in the car, there are only two or three that are really marginal. That is the Fan Fail relay #1 and the Fan relay it's self and I would also look at the head lights relay. Like any mechanical item, the contacts get dirty or corroded over years and need to be replaced. But normally, most will last a long time. The new 40 amp I use and sell for $7.95 are made by a little German company named Siemens. Due to the cost it's normally better to throw away the old ones and just replace them. But, they don't all need to be replaced. They are all enclosed and really impose no fire hazzard. If they don't work, they just simply don't work. It's the wires leading to them you have to watch out for. The thing you have to watch out for are the wires going into the relay sockets. If the connections arn't tight and clean, then that can cause a electrical short, heat up the wires and start a melt down. Also, the device your plugging in needs to have as much contact with the mating connector as possible. You hear about the wires pushing down when a relay is installed. It's good to remove the two screws that hold in the relay's and also press in the connector from the bottom while holding the realy from the top. Then and only then are you assured that the contacts are making as much contact as possible. The less contact connection, then the less connector to carry the current. Remember, Clean and tight.on any electrical connection. That's also why I solder all my joints if possible. As far as the wiring, it's all in the wiring diagram. If your unable to read a wiring diagram, Yes, I have a complete wiring harness out of a original car I could photo and post on the web site if needed. Are you talking about underneath the relay's. John Hervey http://www.specialtauto.com/ Home of the Fan Fix dual 2 x 2.