Nah, the
lights can be cycled via the radio as well. <span class="info"> </span>
True, but the OP hasn't said that he was manipulating the left trim tab and stick to make the lights go on, or pushing any buttons on the DMD to make the lights come on. Either way, the lights shouldn't be coming on.
I still would recommend to the OP, check your battery, check your connections. Then as a last resort, send in the DMD to Tamiya for them to check.