Mower deck not running

I was mowing with my Husqvarna model Yth2448 and the mower assembly quit running. I checked the belts and cleaned the mower assembly--but that was not the problem. I went to my local repair shop and they said it was probably a relay switch, which they sold me. They told me the switch could be found by tracing the wires to the engine. I have done this and looked at schematics of the engine and cannot find a relay switch. Where is it or did they sell me something I didn't need????