Wiper trouble, 98 Sienna

I have a 1998 Sienna LE that has some trouble with the wiper control. The symptoms are:
Off = Off (good)
Timed wipe = continuous wipe at normal setting, randomly going intermittent, then back again.
Normal wipe = fast wipe.
Fast wipe = off
When turning off the wipers, they stop immediately without returning to the “off” position.

All of these symptoms makes me suspect the controls in the steering column. But, when the intermittent wiping is actually working, there’s a faint “BZZzzzt” sound from the dashboard during the pause in wiping. This sound was never there before the problems, which makes me suspect there might be a relay hidden away somewhere that’s the actual culprit. Maybe that’s just wishful thinking, but i really don’t want to open the steering column if i can avoid it.

Any thoughts on something can try before replacing the controls?

Thanks!
-Spazticus