Problem with a 2000 ford Ka?

I live in the USA. I have a 2000 Ford Ka in my shop with a few problems I thought i knew the answer to. Start the car.... check. Turn on the lights... car dies. Restart the car.... turn on wipers....car dies. I ordered a MF switch from UK and 3 weeks and 500 us dollors later same problem. Can anybody help?!?!?!!?