Hi All

I checked and cleaned the grounds as PAhonda suggested - it looks like honda moved the in-cabin fuse box with the steering wheel for UK spec cars, so G501 and G502 are two black wires attached to the same post on our drivers side. All looked sound.

I did pull a favour and got a diagnostic check, which came back with the following DTC codes:

B1075 Headlight Switch Malfunction

B1076 Windshield Wiper Signal Error

B1080 Power Supply Circuit (IG1 Line) Input Error For Relay Control Module and MICU

at this point all was working fine with the car. Instead of leaving it I googled B1080 and found "http://honda.automotive-manuals.com/accord-2002-2007/manuals/000000000000390.HTML", which suggested a few diagnostic tests, that eventually seems to suggest a faulty MICU or a relay control unit. Plus, fiddling with the rear wash seemed to have caused the left side indicators to remain stuck on again. At this point I think I give up, as further diagnostics or MICU replacement seem beyond me.

It's now booked in to Yeomans Honda main dealership at £118 per hour. whatever happens, I will report on the problem and the cure...

 

I think the headlight switch and windshield wiper switch are combined into 1 "part" inside the steering column. Maybe some flaky contacts in there?

Also, I think there's a way to cause the MICU to "re-boot". Something like setting the wipers to a certain speed and switching the ignition on. But the car is already booked in at a shop, so I hope it all goes well.

My trips over there were from 2008 to 2018 so not all that long ago. Sure I saw some large cars, but the majority were a lot smaller than the majority of cars here. I guess I over-stated my observation but one trip my hire car was a 2008 VW Passat estate and in some car-parks there wasn't room to open the doors. I have heard the term "Chelsea tractor" from at least 1 coworker over there.

 

I got hold of an auto electrician today who efficiently ran through a comprehensive diagnostic. He is certain it's the Master ECU (located under the radio). He was certain, based on the following:

Locking and unlocking the car did not activate the lights,

the immobilizer channel was signalling three different statuses in a sub-second interval on his diagnostic,

Both the alternator and battery were reporting either crazy or wildly oscillating values.

Apparenlt these circuits are really fundamental parts of the electrical system, and it couldn't really be anything else. So I will cancel my appointment with the main Honda Dealer on Monday and go for a refurbishment of the Master ECU at a place in Rochester he recommended. Big shout out to Faisal Bashir, based in Basildon- you can get hold of him on 07828097791 if you need a good auto electrician.