If the traffic lights are not working, the intersection is treated like a 4-way stop. That is, as if everyone has a stop sign.
A signal light that is not working.
Anyone driving a vehicle or riding a bicycle should obey a traffic light.
Check out the related link to get a theoretical overview of the operation of traffic lights.
If the traffic light is not powered, you are to treat it as a all-way stop sign. I'm assuming that's what you mean by that. If the traffic light is broken, likely there will be utility workers out there working to fix it and you follow their instructions if any.
Roads should be widened, and traffic lights should be in full working order at all times. Carpool lanes can also ease the flow of traffic.
.... as a stop sign.
If there is a traffic light.
if you hit a patch of ice and you go sliding across all four lanes of traffic, its not working.
It should be treated as a stop sign.
A yellow arrow traffic light means that you should yield in the direction you are going. These are often in place when you are turning left.
look both ways carefully.
Amber (or red) in a traffic light sequence means "stop," put the brakes on! Green means "go;" and yellow signifies that the traffic light is about to turn red (or amber), so you should start to slow down and prepare to stop.