Help with C230, Daughter was stranded !

[wrenchmaster]

My daughter has run out of gas in my '99 C230K at least twice due to the gas gauge not being accurate- it is absolutely unreliable. If she was ugly I wouldn't be so worried about her.... Anyway, I figured the problem was a fuel sending unit, then looked it up on 2 different MB parts websites, only to find that the car supposedly has 2 sending units. Confused, I called my local (but expensive) MB dealer. He said that there is only one sensor and it is located under the rear seat. Does anyone have any experience with this problem? Or suggestions on where the best place to purchase this part might be. I am located in AZ, USA.

I might set you up with my daughter if you help me solve this problem !!