THE BACK UP SENSORS HAVE 3 COLOR CODES. SHOULD RED LIGHT BE IN MIDDLE OR ON SIDE

What is your question?

HOW DO I KNOW IF MY BACK UP SENSORS ARE WORKING CORRECTLY? PLEASE EXPLAIN HOW THE BACK UP SENSORS WOULD GO OUT? ALSO, WHEN THE SENSORS COME ON THERE ARE 2 YELLOW LIGHTS AND 1 RED LIGHT - WHAT DO THE YELLOW LIGHTS MEAN AND ARE BOTH YELLOW LIGHTS SUPPOSED TO GO OFF AT THE SAME TIME? AND WHAT DOES THE RED LIGHT MEAN AND WHAT ORDER SHOULD THE RED LIGHT BE IN? IN MIDDLE?, PASSENGER SIDE?, DRIVERS SIDE? THANKING YOU IN ADVANCE!!