Strange problem

My wife has been having problems starting my car lately. She kept telling me the starter was going out. I would hear it just grinding away but it wouldn't start with her in the driver's seat. Now at first I though it was she wasn't pushing the clutch all the way to the floor but she was. I then gave her my key (she just had a new one made) to see if that was possibly the problem, which it wasn't. It turns out it is something under the seat. She being 5' 4" tall moves the seat up and when she does the problem occurs. I'm 6' 2" and can't even get in the seat where she puts it. Any one have a clue what wiring is under the driver's seat that could cause this. She slides the seat back and it starts fine for her too.