How can you fix the back up sensor in your 2004 mercury mountaineer it stopped working a couple of days ago also the light on the dash goes on when you put the SUV in reverse?

Answer 1

First, have the vehicle in reverse with the key in the ACC position. Remove the bulbs and see if there's power going to them with a test light. If not, check the fuse first. The switch you're looking for will be on top of the transmission... you'll see two wires running into a weather pack terminal which connects to this switch... One of those wires should be hot... take a paper clip, and jump the two wires.. at this point, your backup lamps should come on (assuming you've replaced the bulbs). If not, the switch is not the issue, and you'll need to trace the wiring for a fault in the circuit. Taking the switch out is typically a simple matter of turning it counterclockwise with a wrench... you'll have to figure the size out, as I'm not familiar with that specific vehicle.