Flashing Lights everywhere ?

[blofish]

Have engine out of car repairing cracked head. During process used electrical system a number of times to raise top,open windows ect.. Removed front seats and replaced the fuel pump and sending unit and when turning key to first position all the lights on dash flash in a pulse rhythm? Battery was not connected during repairs any advice would be appreciated. Code reader on the way but thought you guys might have some ideas or experiences like this.