I have a raspberry pi 3 running an LED program on startup, so that when I plug it in, it can run my light program right away, without any input from a keyboard/mouse. Everything works as designed when the pi is plugged into my TV via HDMI, however, does not when it is unplugged from the TV.
When not connected to my TV, the program will start up for about 5-10 seconds, but then the lights stop changing as designed. My program is started on boot by a command being placed in /etc/rc.local.
I've tried other startup methods but have gotten the same result. I've also tried changing the pi's configuration to force output through the HDMI port using the hdmi_force_hotplug=1.
Any help or ideas would be greatly appreciated as this is very frustrating and have run out of ideas!!!! Thank you