steering wheel accessories wiring

Hello all, I've recently taken out my factory built in 6disc cd changer/radio which had volume/station/etc controls built into the steering wheel. On the back of this unit was 3 plugs, the one controlling the radio and speakers was evident, not sure what the other 2 were controlling... I'd like to know if anybody know how i would reattach the steering wheel controls to the new and/or future head units. Thanks in advance Also, i've got a 2003 Mercury Mountaineer Premier Look twice, think thrice, 1 splice/ 1 slice!

This is a phrase i came up with and something i will now live by.

Pac-Audio.com makes several different steering wheel control modules.  All of the big radio manufacturers do make decks that are steering wheel control ready.  The pac steering wheel control modules are radio specific.  You will have to decide on a radio brand before you purchase the control module.