i had a problem with mine, the pins on the rad switch had corroded off in the multiplug leaving me with no HI speed fans, i swapped the switch for a 2wd one and grafted some tails onto the 2 connections , then common up the 2 black and the 2 black/brown wires which makes the fans come on at high speed at the lower setting of the 2wd swicth, when running more boost it helpskeep the under bonet temps down a bit

some pics....