2005 LaCrosse 3.8
Replaced BCM 12/2022 Fixed door lock issues…
Recently wipers started acting up. Now they are always on low. When multi-switch is in high, they go to high (high relay side seems fine).

• Checked relays (continuity, with power, and adjacent fan relay).
• Replaced multi-switch ( no change).
• Replaced motor (no change).
• Purchased access to AC DELCO TDS)

Low wiper relay has power at 87 with key off✅
With key on, low wiper relay has power to 85 which passes 12V through open high relay (87) to low (D-GN) on wiper motor.
No codes on scan tool (borrowed Snap-on Solus Ultra that I don’t know how to use well).
Can toggle between low and high, but cannot turn off motor.
On inputs, the park occasionally blinks from inactive to active?
Wipers alway on doc from AC DELCO says replace BCM, but I’m skeptical…

Any ideas before I spend money on a BCM and programming?

Is the switch off?

Good one!
Yes, it is on low all of the time, WHEN THE MULTI-SWITCH IS IN OFF POSITION and key is turned on to accessory, engine , or when started…
Does go to high when multi-switch is placed in high position…

Seems then the BCM is doing this. I would flash the module. I've seen a flash restore modules several times.

Thanks!
Is flashing it the same as getting it re-programmed at the dealer?

Yes it is.

Does a scan tool indicate the wipers are activated?

Every great story has a plot twist…
This morning, when I came downstairs, my wife said that it sounded like there was a squirrel or something in the car. Sure enough, that’* what it sounded like.
I banged on the body and opened the hood. There was no furry-tailed rodent.

It was the sound of the windshield wiper motor bouncing back and forth as it cycled on and off, or from low-to-high-to-low…
I could also hear the low wiper relay clicking, but not sure about the high wiper relay?
I knew that I didn’t leave the key on, but checked anyway. No key in the ignition? The key was inside on the kitchen counter…
I am pretty sure that the BCM has positive battery power to C1 52 with the key off.
I took the low wiper relay out, and the wiper motor quit cycling.
When I got home from church, I tested putting the low wiper relay back in, but nothing happened (so far)?

Do you still think that re-flashing the BCM is the way to go?

Last week, I opened up the fuse block, disconnected the terminal connectors to inspect the wiring. Nothing questionable or suspicious.

The battery has been starting the car fine, but I did have to jump it after a bunch of time testing ran it down…

Environmental conditions: it did rain yesterday and last night. It was humid, and foggy this morning. The hood was down and everything was dry with the possible exception of the motor, which is in a nook in front of the firewall that can get wet…

I missed your question before I posted what happened this morning…

No, I’m pretty sure that it shows the wiper motor and low/high relay inactive, UNTIL I cycle the multi-switch.
When I cycle the multi switch from off to the first intermittent position, it changes from inactive to a different display for every intermittent switch position, but the motor is in low until the multi-switch is placed in high, and the motor does advance to high (both low and high relays activate to energize wiper high circuit)…

I will look at it again and document exactly what happens…
I need to jump the car because this morning, we realized that the wiper motor was cycling on and off without a key in the ignition, so it drained the battery down to 11.7 3V… See previous post.

I have never used a scan tool before…

Functional Test:
Wiper Low/High Speed Relay
Motor goes to high when ON is selected…

Wiper Motor Relay (Low)
Occasionally, when OFF is selected, the wiper motor will go off for about a second, and then turn back on low, even though off is selected and displayed…
Most of the time selecting OFF, has no effect…

Data Inputs:
When I cycle through the switch, the display on Switch goes from Delay 5 through Delay 1 to Low/Mist/High. When the multi switch is in high, the Wiper High Speed Switch changes to Active.

NOTE: The wiper park switch is toggling from Inactive to Active occasionally…

Also, occasionally the motor does turn off for about a half a second, and back on seemingly randomly…