This first occurred in late summer, after months of no rain as always happens during a California summer. When I activated the intermittent wipers (wiper delay) a variety of aberrant patterns occurred. It has repeated during the few times I drove the car on the few rainy days we’ve had since then.
Occasionally, they work exactly as designed: wipe and then pause, with the delay changing appropriately when I changed the delay time.
A couple days ago I drove to a friend’s house, less than 10 minutes, and wipers worked exactly as designed. On the way home, and then today during another nice rainy day, the delay was normal for a minute or two, then reverted to swiping continuously. On a recent longer trip, they just kept swiping continuously in low speed…which at the time was more than needed.
I found a video online that blames this problem on the relay in the wiper switch. The video gives instructions on how to pull the switch (looks easy) and replace the relay (slightly above my pay grade, but I know someone with advanced soldering skills who charges very little for projects like this). The relay sells online for $5 +/-.
The relay cited in the Youtube video was CQ1-12.
Does this sound like an accurate diagnosis and a correct solution?
Relays are usually pretty reliable. I doubt that’s the problem. More likely the cause is either the module (above) or the switch or the wiring connections between the two. I’m guessing it is the switch that’s turns it on itself. Over time, esp when not used, the switch contacts oxidize b/c they are in contact with outside eair. Relay contacts are exposed to air too, but the relay has a cover which provides some protection, and the relay contact surfaces are is usually larger. The switch contacts have to be small to fit in that location. Oftentimes switch contacts can be cleaned successfully using a chemical contact cleaner product. CRC makes one. It might be more practical to replace the entire switch tho, b/c of the time it takes to remove the switch if needed to get access to the contacts. If you post the circuit schematic here I expect you’ll get more ideas.
A couple days ago, before I knew anything about where wiper electronics were mounted, I checked the local Napa store to see what electronic parts they might have for wipers for this car. The experienced employee searched and told me that nothing labeled as “module” popped up in his system. He seemed somewhat surprised by that, but maybe it’s just that Napa doesn’t stock this module. Maybe they’re available only from a dealer?
The video I mentioned above shows something unlike the module you posted. The video poster explained how to open the steering column and extract the wiper switch, which he claims as being a common problem. His description of symptoms, albeit threadbare, don’t really match my issue.
I’ve since found out that the module you identified is under the dash, apparently attached by screws or tape. I’ll start there - have a look under the dash and see if I can identify the module. Then I’ll work on finding a replacement. I do have to make a trip to the Pick-n-Pull for a long list of things, so I’ll spend some quality time snooping under Sienna dashboards for this module.
Fortunately, this is not an urgent problem since the wipers do work, the only issue is the erratic wiper delay behavior.