Didn't have a multimeter on hand, ordered one for tomorrow. Yes the engine was running, I turned on the power switch and then the Ext2. So I understand there's not need for a second aux battery to make Ext2-5 work, correct?Did you use a multiple meter on the wires after install to check circuit? Have you checked for a blown fuse? Was the car on or the PWR switch on when you flipped on Ext2?