I have a 312d sprinter van that has just developed 2 faults. The first is that the fan only works on position 4. I have 12 volts across position 4 but only 5 volts across 1,2 & 3, any suggestions. The second fault is the main lights went out while on the motorway but when turned off and back on they came back on. Tryed to get wiring diagram from local dealer but told system is down. :?: