Measure voltage against earth on the red and blue wires in C200 white 4 pin connector(attached) with side/fog lamps switched on, if you get 12V your problem might be in the fusebox ar at it's connectors
My friends call me Fery
2000 Discovery Td5 ES manual
Hawkeye v.6, Nanocom EVO,
VDM UCANDAS, oscilloscope
if you think my english is peculiar it means you didnt hear my japanese
ALL MY ADVICES ARE BASED ON MY OWN KNOWLEDGE AND MY WAY OF UNDERSTANDING THE DESCRIPTION AND OPERATION OF SYSTEMS... I'M NOT A LAND ROVER TRAINED SPECIALIST JUST AN ADDICTED ENTHUSIAST.