2006 Toyota Sequioa

what makes the trac, vac, and abs lights come on at the same time?

all the wheels are tied together through the traction/abs system. the computer needs to be able to control the wheel speed for any of those systems. To stop wheel spin or to stop wheel skid it needs to know what the wheels are doing and that it has the capability to affect them. There are times that the lights will come on to tell the system to activate. If the lights come on and stay on then you should have the system scanned for codes.