New HU and factory subwoofer

[WaterBrat]

Sorry if I didn't search the threads enough but I have a simple question.
2005 EB 6CD HU w/ Sub
I want to replace my radio as it has gotten possessed due to bad POT for volume. Do I need to get an HU that has subwoofer preamp output. I am looking on Crutchfield and tell it Factory sub, yet many of the choices it pulls up do not have the preamp out. Is this required to make the factory sub functional?

Thanks in Advance,
Skipper in MX.

 

[Briggslite]

You might be able to find an adapter. OR if you plan to use the iDatalink Maestro RR the harness that you would buy for the vehicle would have a factory sub to RCA (preamp output I guess). Worked great in my 2008 Mountaineer with the Kenwood DNX573s.

 

[WaterBrat]

still looking for a real answer, please.