For amber light, take note of the blinking pattern as it is indication of issue with the system. For the extra wiring connector with marking p4, p7-8, they could be the extra SATA power connector reserve for storage drives connections.  Take good and clear picture inside the machine and the connectors if you want confirmation. 
I upgraded my Dell Inspiron 5675: from 8 gb 2400mhz samsung ram, to 16 gb of 3200mhz of sp silicon ram. Since then I’ve had amber light every time I try to start the computer. I then checked the inside again and I noticed that 2 wires (the p4 and p7-8) have been unplugged. I don’t see any clear spots where the wires could be plugged back in either?
Inspiron 5675, motherboard wires unplugged