[Avitech]

brown/white wire is the alternator side of the circuit for the battery gauge in the instrument panel. The other half is a black and brown wire, (mine is all black incidentally,) to the battery that has a similar fuse to the brown/white wire. the green wire should be the temp sensor if it was routed through the wire gutter at the back of the hood. the blue wire would be for an oil pressure sensor on the v-8 models. maybe your truck had a similar experience to mine and had a swap to the straight six from a v-8 in it's life.