99A4red

What is the difference between starter connection 15a and 50 on a 99 A4 Quatro starter?

I got the car used and the "signal" wire was connected to 15a but now it does not work but when I bench test it and connect a switch wire to the 50 connection it seems to work. I took it to the autostore and it passed their test also.

I am concerned that if a re-install it and connect the "signal" wire to connection 50 I might cause some other problem. Please help......

Thank you