Train him to associate the dryer or anything he is scared of with positive experiences. I have a blow dryer in the mail so here's what I will do in steps/sessions:
1. Show him the dryer but don't run it. Treat (T) while he checks it out, give him time.
2. Have someone hold the dog at a good distance away and run the dryer briefly: T.
3. Run the dryer: T, turn it off, no treats, turn on: T etc.
4. Make the sessions of running it longer gradually while feeding treats, you may need a helper to operate the dryer.
5. Gradually move closer to the dryer with the dog and repeat. Watch for signs of stress and if you see that, increase distance and repeat the process.
6. Briefly blow on his toes, up the legs etc. Lots of treats/play.
It is crucial to make the dog succeed. Do not force it or correct him. Remember that you know the dryer is not going to kill him but he doesn't. If he is toy driven, use toys instead of treats.
I have used these techniques for all sensitization exercises: vacuum cleaners, going in and out cars, scary guys with beards and hats, parades etc.