2004 Freightliner has 2 possibles for a harness. BT00147 or BT iso Din. Pulling the radio would tell wich one to use.
Radios we sell come with the harness if you tell us what you have so I might suggest the JCV1640BT no CD or the NEW JHD36A CD.
If either one of these radio were wired with the BT 00147 harness they would cover either or harnesses, because they are plugged with the BT ISO DIN style connector.. This would guarantee a PLUG & PLAY for sure