Motion sensor does not appear to be working

It is likely to be the relay inside the wire compartment or possibly the motion sensor causing the problem. When the motion sensor clicks, it sends a signal to the relay and that changes the speed from idle to high. It is easy enough to unplug the current motion sensor and replace the whole grill assembly with a new one. Swapping out the wire compartment is relatively easy but we recommend a certified electrician complete the work to ensure that the unit is wired correctly, and most importantly, safely.