Our trucks and motors are getting old, just a thought...

[ynot]

The engine harness comes from Cummins the dealer can get them for ya, an the firewall back is an OEM spec harness so it has too come from the dealer, your truck probably has a couple different harness depending on features an specs I know kw an Pete harness are like that, so blindly ordering one online is probably not a good idea unless you have the exact part number.