My windshield wipers are doing something funky - Help!

So I’m driving to work this morning, and there is a light rain. I turn my wipers onto the lowest setting (I only have four speeds - off, low, intermediate, and high). Out of nowhere, the wipers sped up by themselves, but only for a couple of swipes, then return to normal. A few minutes later, a repeat. This continues the entire (though short) drive.

So what gives? It’s an older car ('91 Toyota Celica), so it doesn’t have anything fancy like rain-detecting wipers. I tried turning the wipers off and then back on, but that didn’t seem to help.

My guess would be an intermittent short circuit in the wiper motor or the wiper switch. The cure would be to replace the faulty part. Testing would be necessary to determine where the fault lies.