Cae electronics; my good deed for the day?

[gareth evans]

Sitting on the bog with window open because of the weather. noticed a car on the green opposite with one rear light turned on.

Went to the bog again a couple of hours later (Pepsi Max is a diuretic?) and the light was still on, so trotted across the green and banged on the door.

It was a 2018 Ford Focus and the owner commented that although the lights were turned off on the dashboard, that there was an LED indicating that a rear light was on.

He turned all the lights on, and then turned them off and they all went out.

So, is this an example of too much electronics in a modern car? Do the lights get supplied with 12V all the time and rely on transmitted messages to turn on and off, and had the rogure light lost its message?

The EMU was a definite good development in a car because if the battery is good, then the car will start, and no more does one piss about with point and plug gaps and dwell angles, but perhaps all other electronics is overkill, including the ABS because how often during the year do you actually have a skid?

Just because electronics can be used all over a car is not a good reason for doing it.

COme back the OC71, all is forgiven! :-)

[Fredxx]

Or even a software bug. Perhaps the guys who wrote the software for the Toyota Lexus ES 350 sedan now work for Fords?

Most systems would incorporate a handshake.

I don't think the OC71 was man enough to drive any light bulb!

[Clive Arthur]

<snip>

I have an old Citroen Xsara Picasso. I don't do many miles, it does everything I need and I don't care much if it gets scraped. Or even scrapped.

The remote locking stopped working, no biggie. Then you couldn't lock one of the passenger doors, again, not a real problem.

Then one day I noticed that the dashboard display had switched to German. Well, ok, not worth bothering with, but at the same time the locking started working again.

Probably all written in C, an inherently buggy language.

[Dave Plowman (News]

Are you sure it wasn't parking lights? German made (or spec) cars often have those operated by the indicator switch, engine and light switch off. Although should give you a warning if you turn off the engine with the indicators going.

The lights that are on in this condition are one side tail and front only.

[Fredxx]

It is a bare metal language, but there are coding standards like MISRA that should reduce the incidence of bugs.

There are also watchdogs and for safety critical system there should be some form of monitoring oversight.

[charles]

my Cortina - 1971 vintage - did that.

[Brian Gaff (Sofa]

Every time that spider gets across the FET gate and supply rails it turns my light on kind of problem. I had something similar, not even in a car, but in a home made burglar alarm where sensors monitored the resistance of the various sensors, but it was just too sensitive and when an insect got into one of the junction boxes the alarm went off, as it also did when there was a nearby storm. Great fun those years though, though the long suffering neighbours might not have agreed. Brian

[Peter Able]

There may be an alternative explanation. With my car, and many others, you can arrange for this to happen intentionally - as a means of providing a "parking overnight" indication. The sequence involves the direction indicator switch as you have to able to select which rear light is closest to vehicles approaching from behind.

If so, when your neighbour fiddled with his car, the "parking overnight" chain of operations was cancelled.

Nothing is certain in this world, but the key dumbness in most cars is not down to the car but to the occupant of the driving seat.

PA

ps those of a certain age will remember trucks and artics parking up for the night. The last thing the driver did was to hang an oil lamp on the appropriate side of vehicle's rear-end.

[John Rumm]

Most modern cars will control all that kind of stuff using a CAN (Controller Area Network) bus, since it dramatically reduces the amount of loom wiring and makes integration between various sub systems much simpler.

So you just need to wire power and data to each device (be that a sensor, a control, or an actuator of some kind).

Its a broadcast only network - devices don't have point to point conversations. So a control like a light switch, will simple broadcast a message to everything else on the bus, to say that it's a light switch, and it is now in the "on" state. All the other devices here this, and those that have an interest can choose to do something - so the controller for the lights can turn the lights on. The controller for the indicators however will also hear the message, but not care.

[charles]

My father has a lamp which ran off the car battery showing red to the rear and white to the front and a elecromagnet to hold it on the door pillar.

1950s

[Dave Plowman (News]

There was one Ford of the era that wouldn't start if left in that mode. You had to return the indicator switch to off.

My last few cars have been German made. They still have this parking light feature. Which I do sometimes use, even in London.

[Peter Able]

Thanks, both - now you remind me I can recall them.

Says a townie ! No street lights at all in this village. :-{

PA

[Max Demian]

I altered the wiring of my Mk 1 Escort to do that, after wiring the headlamps through a relay so they would only operate with the ignition on. Otherwise you could flatten the battery by forgetting to turn the headlights off.

[Max Demian]

They usually clipped over the side window glass, then you wound it up.

Hardly needed nowadays as most roads where you're likely to park have street lights.

[Dave Plowman (News]

Oddly the indicator witch in my SD1 Rover has been designed with parking lights in mind. But the UK version not fully populated with the necessary extra contacts. The switching is actually quite involved, as it disables the number plate lights and instrument lighting too. And in the case of Ford. the starter too. Much easier these days with a canbus system.

[alan_m]

There is a parking light position that in combination with the direction indicator stalk turns on the lights on one side of the car. The owner could have mistaken this position on the light switch with the off position.

[gareth evans]

'twas only the near side rear.

[Tim+]

Um, strictly speaking, only the rear was *noticed* to on.

Tim

[Dave W]

My last car was a Citroen Xsara. One day I was told that I was doing

80 although my speedo said 70. I made a conversion chart, but then things got worse - at one point all lights flashed randomly and the two moving-coil meters pinged from side to side.

The garage said I needed a new control board, but when they tried to install it, it wouldn't communicate with the engine managemant computer because it was a different vintage. So I had to have both boards replaced, costing me £2000.

I resolved not to buy another French car in case the elctronics came from the same factory. I now drive a Seat Ibiza which has been faultless for the 10 years I've had it.