I've had the same problem. The heater and the blower start up but there's no smoke coming out. Now you might think you need a new smoker or even a new control board.
Take the top 4 little Philips screws off the top of smoker heater. Not the blower, the heater. Take out the the cotton package inside the component and gently wring it out - let it dry out. Then gently put it back together. The problem just might be that the cotton in you heater is over-saturated. When this happens, it won't work anymore. Maximum application of smoke oil to your heater is about 10 drops; anymore than that and you risk 'drowning' it.