I replaced the ICU with a new one

I can hear the switch (oops...meant relay) doing it's job and pleasantly watch the wipers do their job, as long as the headlights are on.

 

You did keep the old ICU, right? Carefully remove the new ICU, package it nicely back in the box, and return it for a refund as soon as possible.

Did you really do all of the ICU input tests in the diagrams? Especially make sure to test continuity of the ground wire at cavity A14.

If you remove fuse 30, do the intermittent wipers still work when the headlights are ON?

Do you have daytime running lights? If so, does having them ON cause the wipers or other functions to work? Does having the parking lights ON (no headlights) cause the wipers or other functions to work?

Do you see any electrical damage in the fuse box, especially where the ICU plugs in?

 

I'll have to tackle it again on the weekend; I'll definitely test the fuse scenario tomorrow.

I do have DRL's, and the intermittents will not function with just the DRL's on, but with just the parking lights on everything functions properly.

There was no damage apparent in/around the fusebox, and everything was dry and dust free.

Thanks for the help, hopefully my next post can claim victory.

 

Do you have a multimeter? You must have one to do the input tests, in particular the continuity test (=resistance/Ohm measurement) of the A14 ground wire.

My current guess is that the ICU A14 ground wire or terminal may be bad. This might force the intermittent wipers/alert functions of the ICU to find a ground source through the dash lights circuit protected by fuse 30, possibly explaining why these functions work only when the parking lights are turned ON. Also check whether the A14 pin is bent/damaged at the rear of the fuse box.

 

I think it's time for me to invest in a multimeter. At lunchtime I'll start by checking the ground wire visually; sounds like it grounds under the dash by the blower motor and testing the wipers without the fuse/lights on.

 

You should be able to purchase a basic, adequate digital multimeter for $15-$20. Yeah, first check whether the A14 pin at the rear of the dash fuse box (see diagram) is bent or damaged. I think this ground wire eventually ends up behind the driver's kick panel.

 

Tested the wipers /w lights on, fuse 30 removed, same issue.

Will buy this multimeter shortly (might pony up for the auto-ranging one), or barring that borrow one from my office.

Will update after the tests; hopefully with good news.

 

Managed to test a couple of wires before it was time to get my daughter up for lunch.

Regarding the first test, Cavity A14; condition: All conditions.

Does "all conditions" refer to all the other conditions I'm testing the other cavities and/or wires under? Or does this mean that no matter what there should always be continuity? So far A14 has tested good. Hope to finish off the testing this aft.

Rather hard to squeeze myself under the dash and position my light, inspection mirror and use the probes without knocking the mirror and light around. I think I may hire a primordial dwarf to do the testing next time

 

Yeah, all conditions simply means you don't have to turn a switch or the ignition key. The ground wire should always have continuity. Also make sure the male and female terminals of A14 are not damaged and able to make good contact.

I know how you feel. Maybe removing the fuse box would help with the access problem. You might also consider removing the driver's seat.

 

Testing complete. Thanks again for the great advice Ron, was able to learn a new skill, and not be so terrified of wires and potentially fubar'ing them.

The only very curious result was the test on Cavity B10, should be 1V or less, I got ~4V. This points to a poor ground, faulty ignition switch*, or an open wire.

Another curious result, although not a fail by what I read in the document you posted, was a voltage of 0.45 on cavity B4.

Was hard to get a good continuity reading on B1/B2, but I did, figured it had something to do with the thickness of the insulation, and they were hard to reach.

*there's no stamp above the 8th digit on the VIN located in the engine bay, calling my stealership to verify if the recall has been done prior to my buying it last year.