"Don't put a crankshaft in it if it only needs an air filter"
In other words, check the simplest things first. They are usually the cheapest as well. First the fuse. If that's not it, the button for extenstion and retraction on the dash like "m3456y" said.
There is a relay that is next. Still the cheaper direction. Lastly, the motor. Honda is overly proud of any motor they use and it wouldn't suprise me if a new one is over $200 ea.
The service manual should have a trouble shooting guide.
Remember, something caused them NOT to go down so make sure when you find the problem it's the end cause of the failure.
Don't just swap the parts, fix the root problem so it won't repeat.
Cheers
nigel