Finally got bit by the Prince of Darkness. Never had any electrical issues, but today is a different day. Crazy rain on the way to work this morning, and in the middle of my commute all the instrument cluster gauges died, the cluster illumination lights came on, and either turning on the left directional or the hazard flasher brought the gauges to life momentarily during the flash cycle.... on, off, needles up, needles down. Crazy stuff. Pulled into a gas station and shut the car off to fill up, and had some difficulty restarting - stone dead in Park, lots of difficulty getting it out of park, and was finally able to get into Neutral and get going again. I'm hoping that someone will say Oh yeah that happens all the time, and the cause is ..... and be able to point me in the right direction & save hours of tracing schematics and wires. Any help & suggestions would be appreciated because this one baffles me, thanks

 

I'd look at the turn signal stalk. Known to go bad.

 

check your battery, battery terminals, and grounds also. seems simple, but is often the problem.

 

Did the stalk cleaning relatively recently, would suspect that but the powering up / powering down of the instrument cluster in tune with the flasher stinks of a grounding or relay issue, and there's some buzzing now coming from somewhere in the vicinity of my left shin, especially when I apply the brakes or turn on the directionals. It seems that all these subsystems share a common grounding point E201 which is supposed to be somewhere in the area my left ankle, when sitting in the vehicle of course, seems as good a place as any to start

 

Went through all relevant grounding points common to all the affected circuits, nothing. Re-took the stalk apart and made sure it was sparkling, nothing... except for the added fun now of the fuel pump spinning up when the stalk is in the parking light position, and of course the p-lights are dark.... WTF ! I'm starting to think maybe a power sourcing issue or circuit to circuit short somewhere rather than a bad ground ??

 

Your ecm probably got wet, and hasn't dried out yet

 

Checked the ECM, seems high and dry with no obvious signs of wetness on it, near it, or anywhere in the engine compartment. From looking at the Rave, it looks to me like the functions affected don't run thru the ECM, but it's hard to tell. Once I get it started it runs beautifully, and it seems like all the functions controlled by the MFU are working correctly as well. Turns out the buzzing is coming from the flasher relay, which now buzzes pretty much constantly when key is moved to position II or the lights are on. Is there a common power circuit, ground, or splice point for the rear lights and fuel pump? It seems more than coincidental that when the lights are switched on (no key) the fuel pump is turning on instead of the rear lights