I bought one of these from Car Toys at the same time I bought the system. The first unit was not functional and I returned it. The second unit would work only sporadically. I returned it for a third unit, which worked like the second. I tried fresh batteries, no difference. I had Car Toys check the receiver but they could find nothing wrong. They verified that none of the three units would work reliably and took them back, no questions.If, as another person has written, the units are IR rather than RF, I'm not surprised they work poorly. My opinion: Avoid this product. It's a bad design.