3rd Gen Rear Wiper. BCM bug.

[cmartyn]

Saw this on a YouTube video.. sho enough. If you have the rear wiper on and turn the car off and back on the rear wiper will not come on. You have to cycle it off and on again. Not a big deal. Not as stupid as the fog light accesory bug but still a bug.

[VStar650CL]

I'd be interested to know if the bug is in the IPDM or the BCM, since it's the IPDM that actually drives the wiper motors. I'd also be interested to know if the error persists after the BCM hibernates (30 minutes) or if it only happens during a shorter key cycle. I'll try to get hold of a lot car that I can play with and maybe find a fix or work-around.

[cmartyn]

Cool cool.. Logically, to me, the i/o and processor are all in the BCM so its not scanning the stalk switch. When I tested it I had it on intermittent. I also only shut it off, opened the door, closed it, and started it back up.

[VStar650CL]

Cool cool.. Logically, to me, the i/o and processor are all in the BCM so its not scanning the stalk switch.

I'd think so too, but the IPDM and BCM both remain "alive" when the car is shut down, so it's possible the IP is supposed to remember the setting until countermanded. That's the crappiest aspect of distributed processing. It would be one thing if they gave us flowcharts for the firmware, but that will never happen.

[cmartyn]

I have this new game idea, its called jump to conclusions! I guess its possible it doesn't even go through that stuff too. I dunno. Looking at a 2016 manual it makes no mention of the rear wiper in the IPDM at all.

[VStar650CL]

No, you were right, for sure the combo switch is read by the BCM. But from there everything is CANbus, so who actually stores the memory is a guessing game. The BCM may be reading the switch correctly but not responding to it because it expects the IP to remember the last setting. Nothing new, we fight with that sort of "who's got the button" crap all the time.