FMC wrong frequency

Can anyone tell me where the PMDG 747 FMC reads the airport frequency for the proper ILS landing. When I approach runway 34L or 34R at KSEA airport, the FMC frequency is not correct hence an aborted landing. The FMC shows a frequency but not the correct one. Can someone tell me what file the FMC is for reading for the correct ILS frequency. I cannot find this listing anywhere so either I am missing it or it cannot be corrected.

Thanks

Set up the desired approach in your App/Dep area, where SID/STAR etc are, so pick ILS Runway 34L at YSSY for example, and it should fix it up for you. (Don't quote me on that, I haven't flown them in a while and I'm going off memory). Or you can manually enter them on the radio stack.