Why does the Dirt Finder Light on my Hoover Vacuum always stay red?

Some Hoover vacuums are outfitted with an "Embedded Dirt Finder" system. The light stays red while dirt is being picked up and then turns green when there is no more dirt being picked up. This is accomplished by the placement of a small microphone like sensor in the ducting just before the dirt enters the bag.

Unfortunately, after some time. The sensor stops reading correctly and the light always stays red. One can fix this problem by following these steps.

1. Unplug the vacuum
2. Remove the bolts holding the handle on and remove the handle
3. Remove the screws holding on the rear part of the housing that covers the hose inlet on the back of the vacuum.
4. Remove the hose inlet and the sensor with black and blue wires attached to it.
5. Vigorously clean between the two contacts on the sensor or even scrap away dust and dirt with the edge of a screw driver.
6. Before reassembling the vacuum, plug it in and turn it on. After a few seconds, the red light should go green.
7. Re-assemble the vacuum if the light goes green, otherwise repeat steps 5 and 6 until it does.

I hope this helps. Staring at the red light can be very irritating if you've become addicted to staring at the green light while you vacuum.