Audio Systems: factory to aftermarket, pioneer unit, cassette stereo

Question
Lets say I have a 98 Silverado with the factory am/fm/cd/cassette stereo. It has the remote cassette deck in it and I am wanting to upgrade the head unit to a Pioneer or another type of direct fit stereo. The Pioneer unit has an auxiliary input so I was wondering is there a way to use the factory remote tape deck with the Pioneer unit or maybe some other aftermarket head unit with the aux input?

Answer
yes you can the tape deck  have a 9 pin plug  
there is  7 wires there  3 are audio  2 are power 1 is ground and the other triger back to the radio
if you send power the unit will work just wire the aux input from any radio into the output of the tape deck
the cable are eeasy to recognize
good luck