Crazy electrical issues
 

After 225k of great service, the Accord has finally caused me a real pain. All of the sudden bright lights stopped, turn signals, one power window, keyless entry, one power door lock (not the same as power window), instrument lights also not working. I took the computer out and everything looked pristine there, checked fuses and power going to FB, all good. Anyone have any ideas as to what could be feeding these? It seems weirdly random for it to be a short.

Year? Model? With that information someone around here can probably find a circuit diagram & see whether all that stuff has a common fuse, or a common ground or something like that.

Sorry, its a 2005 LX 4cyl, manual if that matters.

Sounds like an issue with the multiplex control system.

Check/re-check under-dash Fuse No. 21 (7.5A) and No. 7 (10A).

Thanks for the quick reply, they both checked good with meter. One was labeled backup, is that correct one? Could MCS be bad?

There are several control units that are part of the multiplex control system. Your symptoms are more likely related to the Multiplex Control Integrated Unit (MICU) that is integrated as part of the under-dash fuse/relay box.

The MICU may possibly be bad.

But, there are grounds wires (G601) under the carpet of the left side of the car that go to that MICU and also another ground wire (G502) under the left side of the dash that goes to the same MICU.

Check any gounds too. My ex Fiesta when it was new had a technical service bulletin about the ground from the battery to the body. It was only a year old at the time. My low tech Corvair has had several grounding issues, but not really the same technology. It has only seven fuses!

Could you clue me in as to where these grounds are? I looked under the carpet drivers side and didn't see on going under, but I didn't take it completely up and may have missed it

See attached photos. G601 ground is different between 4-door vs 2-door.

Much appreciated