You can certainly get replacement triggers for Makita – I've repaired one for my stepson.

They usually comprise little more than an FET, a variable resistor and a reversing switch. You may have had a wire come lose.

Neil

As Neil has said there are just three components, you will need to take the drill apart and located the trigger assembly module not always easy, and putting it together again can be a real pain. If you like I can send you a PM regarding testing the Mosfet once you have got the drill apart and have located the MOSfet, which I think might have failed. although I have known the switch to be full of grit etc and its failed. No doubt you have a camera phone take plenty of pictures as you go, as trying to remember where all the location of all the wires later is not easy. Unfortunately other manufacturers switches etc will not fit. You might need to go to a car boot sale and lookout for an identical drill as a source of spare parts. If you do locate the fault and its a complete unit which is needed, a firm by the name of Cars in Boston Lincolnshire has been a good source of spares for me in the past. I think I found them via Google.John