2008 GMC Sierra 3500HD remote start works good but now the key will not start the vehicle

Question

I did not hook up any additional wires only the harness is this maybe the issue?

Answer 1

Nothing extra needed aside from the harness.

Here are 2 things to check.

1. Put oem harness back and see if starts.
2. Check fuse labeled DLIS or discreet logic ignition switch. 2-5 A fuse