Looking for some guidance here....

The radio in my truck (2002 - 1500 Quad 5.9) is not working, the little red security light is flashing & clicking when the key is off, the remote won't open the doors, the doors can't be opened by the door switch either. However, the remote does work when the key is turned on. Truck runs fine.

Any ideas?

 

I would start by checking all of the fuses. Sounds like maybe the (keep alive) memory fuse is blown.
The ignition switch would be my second check if the fuses are all good.

 

The fuses are all fine. How do I check the ignition switch?