Greetings. Can anybody help me with an electrical schematic or just some ideas on where to look. My buddy has a '96 dually, 7.3PSD, 5sp.4X4 My problem is, what all is in the speedo circuit? I have no power to the VSD(?) on the rear axle. The odo is up but doesn't advance. the Chilton manual I have gives me more ?s than answers. Help, please