This is a 1998 Plymouth GV with a 3.3 V6 under the hood and 175K miles I bought used a bit over a year ago. Works great except for a few minor things that I can throw money or time at, and this big one.
If I turn on the wipers in intermittent mode, they will either 1) work correctly, 2) work correctly and then stop entirely, 3) possibly swipe a few times in rapid succession before either of the two above - or even doing it again after the given delay, or 4) carry on as if they were in either low- or high-speed continuous.
Now, if anything BUT 1 happens here, I may turn them off, and watch as 1) they swipe once and return to normal parking position, 2) keep swiping a few more times and return to normal park, or 3) keep swiping a few times, and then park in the apex position, leaving me to pop on briefly and let them re-park.
I have heard several possibilities, pointing to the wiper motor, wiper fuses, wiper relays, and I think I heard one guy say something about headlamp fluid. (I don’t talk to this last one anymore as a result of this.)
It’s obviously not a fuse, as those blow and make the wipers not work. I’m guessing it’s the relay - the motor, if it were going, would also just fail, whereas relays on a 12 year old minivan, if original parts, would possibly stick.
This said, can I get a second opinion?
My first reaction is to say the motor. The switch is a possibility, but the motor has much of the function integrated into it.
The switch is probably malfunctioning because the rheostat portion which controls the wipers is bad. Does the switch work normally in the fast mode? If it does then it’s probably the switch. If the switch is the rotating type you can rotate the switch back and forth very quickly several times and see if it works. This usually fixes a GM switch for a short while. This motion is just wiping the rheostat contacts clean.
I had a couple of 90’s Chryslers. I hope your problem is just a relay for the intermittent wipers. One of my Chryslers had a similar problem, until one day, the switch gave off some smoke, and then nothing on the wand worked. If this is one with a wand style switch (which has wipers, bright lights, and blinkers), it is called a Multi-function switch for obvious reasons, and you are welcome to read gripes about them on various websites if you like. These have been known to fail. Apparently, the contacts inside the one piece unit cross and short out or just wear out, so you have to purchase the entire assembly. When I bought the new switch, the dealer was the only place to get it and it cost about $250. Good Luck!