Hello everybody.
I've come to your forum to help me narrow down an electric issue on an old Honda local car "gurus" have been unable to help with.
It's a 1999 Euro-model Honda Logo. Think of it as a Sixth Generation Civic's smaller sibling and as the Jazz/Fit forerunner.

The car has been extremely reliable in 16 years of ownership, but in the last year it has developed the following intermittent fault.

While driving the ABS light start to be dimly lit, then the key reminder light comes on and finally the car dies. The first two times it happened I was able to restart the car right away without even cycling through the ignition. The last time it required several attempts. On occasion I've also noticed the "whirring sound" from under the bonnet (fuel system being pressurized) appears to sound strange. I cannot exactly descibe it.
When the car shuts down, the radio stays on.
Given I have other vehicles, this car is little used and often spends whole weeks without being used, hence I gave it a low priority. Now it's time to decide to either fix it or swap it for a new model.

I installed a new battery and ran a charge test and was able to rule out the alternator.
I narrowed down the possible causes to one of two: ignition switch and main relay.
If this can help the car uses a Mitsuba RZ0088 main relay, same as on old Accord's.

I tried replicating the fault but had no luck. I also tried driving on a very bumpy road and jiggling the ignition key but had no "luck" there either.

Now, I could let the Honda dealership sort it but there are two problems.
First, the "local" dealer is very friendly and highly competent but it's also 30 miles away.
Second, if it's a relay I can fix it myself in minutes for the cost of parts, but I fear an ignition switch traspant may be worth a good part of the car value. In that case I would seriously consider replacing the car.

Thanks to anyone who will help!

 

Update. I managed to find a cheap genuine Mitsuba main relay from Germany. It should be here late next week. For the price, it's worth a shot, otherwise I can keep it as a spare or sell it for the same price.

Given how intermittent the fault is, it will probably take a while to see if this fixed the problem, otherwise I'll get the dealership to quote an ignition switch replacement and decide on the car's future.

 

Sorry for not updating before but I had some personal issues which really needed my time.

Changing the main relay seems to have cured the car. So far no more issues despite all my attempts to replicate the fault. If it worked, it was far cheaper than planned.