Aftermarket radio

[Dp247555]

Do you still have to disconnect the aftermarket wiring harness to tune like with the T1000 or does the T2 have the ability to tune with it being connected?

[06MonteSS]

on your older 2003, yes....

You need to make sure anything aftermarket is disconnected/pull the fuse for - anything like aftermarket stereo, subs, amps, nav, alarm, remote start, seat heaters, trailer brake/light setup, etc.. anything like that, their wiring harnesses need to be disconnected/pull the fuses for it before you try to tune anything...

also make sure everything is turned off inside the truck.. lights, radio, heat/fan/blower, do not operate power windows, put your parking brake on, etc...