Bl**dy computers and their programming

[nta16]

On the way back from the micropub my wife declares that the orange triangle of doom has just appeared on the dash display.  As passenger I turn on the 'radio' (infotainment unit) to see what  the 'Car' menu can tell us.  Rear brake light.  Now, very unusually, I remember we had this a few year back, at the time  I went to replace the bulb to find it was fine so I swapped it to the other side of the car and left the new bulb where it was after checking and cleaning the contacts.

 

As we were more-or-less passing Halfords and I'd given away my stock of brake-light bulbs to neighbours over the years we called in to refresh stock.

 

After the purchase I stood in the rain at the back of the vehicle to see which side the light was out - none of them!  The computer had ****ed me about again!

 

Back in the vehicle and dry and no more orange triangle of doom showing, me wet but with a fresh stock of "25% longer lasting" bulbs as the "heavy duty" bulbs were no longer on sale ("heavy duty" was made to older normal standards as opposed to the alternative of **** poorly made modern parts).

 

I wait for the computer to have another mardy moment.    

Edited 21 August, 2021 by nta16
speeling and stuff

[Norton Ian]

If it's like my old Octavia, it doesn't use a standard 21/5w watt bulb. It uses a 21/4w and that watt makes a difference as warning light stays on if you fit a 21/5w. Confused me the first time I replaced bulb as had never encountered a 21/4w before. Halfords do sell them though. 

[nta16]

I just looked it up and that's a bulb I had as a spare for years, offset pins.

 

P21/4 - (Ring) R566 - (Lucas LLB) 566

BAZ15d - B = bayonet, A = I think is for small (bayonet), Z = I guess is the type of offset (pins), 15 = 15mm width of cap (base), d = double contact.   (semi-) 

 

Why we have to have so many different parts doing the same job is beyond me. 

[nta16]

To add insult to injury I've just put away in the shed the two new 'Halfords 25% Longer Life' bulbs to find I already have two unopened (ring standard) so now we have a choice of what to use.

 

[rum4mo]

1 hour ago, nta16 said:

To add insult to injury I've just put away in the shed the two new 'Halfords 25% Longer Life' bulbs to find I already have two unopened (ring standard) so now we have a choice of what to use.

 

I know how to do that, years ago when we had a small bit of grass to cut, I bought a Flymo, so now and again I needed to buy new cutting "fingers" for it. Then, one Spring day we went to a garden centre and I bought a new pack of "fingers", and opened the glovebox of wife's car, a Fiesta 1.6Si, to put that new pack somewhere "safe" - and there was the previous pack, very annoying!

 

Bulbs are only getting worse, though now mainly they are long life versions in newer, trickier to find and more expensive than when they were just the regular types, so changing most lights to LEDs has just ended up making your bulb spares kit a lot more expensive - and meant my box of "now not needed on ours cars" new unused bulbs, is getting quite full!

Edited 22 August, 2021 by rum4mo

[nta16]

Other than changing a few bulbs that have blown or gone silver/black on other people's cars I can't remember having to change many bulbs on our cars since at least 1985 (first Skoda!) - or I've forgotten, which is very likely.

 

Before even these computers messing me about with brake light bulbs I had a neighbour's car do so, it was a Mk4 Cortina, but far from new at the time.  I noticed his brake light out so offered to change it with one of my stock.  To cut a long story short the replacement bulb was intermittent because when the filament was hot it broke but when it cooled it touched again.  As my neighbour was pressing the pedal and lifting off on my instructions this made diagnosis less obvious until I told him to keep the pedal pressed and then tried the replacement bulb in the light cluster on the other side.  I have seen this with a filament before  but I was thinking the light cluster, it's connections or wires might be at fault.

 

Though very many years ago this may have been the start of poor quality car bulbs but I didn't get another dud car bulb again until many years later.  I needed to replace, da dah, a brake light bulb on my wife's car after 7 years of ownership so thought I'd change both sides brake light bulbs and keep the working one I took out as a spare.  I'd bought a spare bulb kit for the car when it was new and it had the dud brake light bulb just sitting there waiting.

 

IIRC at that time  Halfords sold "Heavy duty" brake light bulbs, which I imagine were the old days standard (and only) quality with non-heavy-duty bulbs being the poor quality modern versions.  Later I noticed Halfords and others selling 'Quick response'(?) bulbs.

 

After at least the last15-20 years of **** poor modern made parts for "classics" (over priced and over-valued old cars) I'm much more used to over-cheap quality parts and as every year (month?) passes I expect to see more of these quality of parts on more modern cars .

 

All factory bulbs in the Skoda AFAIK so hopefully the car's computers will look favourably at that.  

 

Edited 22 August, 2021 by nta16

[JGrindel]

The filament is blown. Just as it heats up it welds itself together again. Hit a pothole and it will fail again. 

[nta16]

4 hours ago, JGrindel said:

The filament is blown. Just as it heats up it welds itself together again. Hit a pothole and it will fail again. 

Hi, JGrindel, yes that is possible, as with what I put above about the Mk4 Cortina bulb, but I don't think it's the case this time as the brakes have been applied numerous times since and numerous potholes have been encountered.

 

I did a few easy tests like having the brakelights on continuously for a full two minutes then during the third minute tapping the lenses and applying about 14st to the hatch sill to get the suspension bouncing.  I didn't bother removing the lenses to get at the bulb as I don't like fatiguing, particularly external, plastic unnecessarily

 

It might be a wiring or connection problem somewhere but if it is it's very internment so far.  Having decades experience of car wiring and computers my very small bet remains on the computer(s) but if I'm wrong I will report so as I'm not a mechanic or auto-electrician with a reputation or ego to protect or want or need to blame someone or something else as I already have a large collection of personal balls-ups so one more makes no odds.  😄

 

I realise as I don't have proof it's the computer, or wiring or connections and it's easier to eliminate the bulb so that's now what I've done, just replaced it based on your post (as usual I forgot to test the new bulb before putting it in). I gave all the bulbs and connectors a quick spray of electrical contact cleaner, Contralube 770 on connector pins and cleaned the cavity area behind the light unit.

 

Sod's Law the bulb didn't light up, on testing the bulb it was a (another) dud!  This was a bulb from previous boot stock, when Halfords used blue background on their labelling (before current orange), looked absolutely fine , new never used and stored in shed so no vibrations.

 

(Moan, moan.) Another play with the polished lens unit that tries to escape your hand like a wriggling fish, risking breaking the tang hooks again on the plastic for bulbs holder plate, then pushing the whole unit on its two stud locators to try to line up correctly for the two screws - what a ****-poor design and fiddle and farting about to change a bulb. (Moan, moan.)

 

If I remember and can be bothered I'll solder wires directly to the bulb I took out and connect it to a 12v battery and leave it alight while I try too literally shake the life out of it.

 

(Moan, moan).  Oooh, the utter joy of farting about with cars - I still think it's the computer(s) though.  (Moan, moan).  😒

 

Edited 30 August, 2021 by nta16

[johnh510]

22 hours ago, nta16 said:

 

(Moan, moan).  Oooh, the utter joy of farting about with cars - I still think it's the computer(s) though.  (Moan, moan).  😒

 

Your grumbles are likely due to the programmer of the "computer", or lighting regulations the programmer was following.

 

AIUI, the lamp failure is decided by "the computer" measuring the resistance of each lamp while it is not powered up, and comparing the values returned with a maximum and minimum value. Resistance too high - a lamp has failed if the value is huge because it is open circuit.

 

That seems fair enough, but the regulations appear to specify a minimum light output of 4 Cd, and a maximum of 8.5 Cd for a composite stop/tail lamp.

Hence a lamp which is "working" can fail for being too dim, or too bright.

 

The regs I found (which may or may not be relevant) are here

 

https://unece.org/fileadmin/DAM/trans/main/wp29/wp29regs/2015/R007r6e.pdf

 

Likely section 6.1.3.1 but I dozed off before reading/understanding it all....  

 

ZZZzzzzzzz.....

ZZZzzzzzzz.....

zzzzz.....

 

Candelas?

 

ZZZzzzzzzz.....

ZZZzzzzzzz.....

zzzzz.....

 

ZZZzzzzzzz.....

zzzzz.....

[Breezy_Pete]

Could even be the brake light switch getting a bit resistive, depending on how/where the test current through the bulbs is monitored.  Don't have wiring info for mk3s though, so no real idea. 

Seems a bit too young for such a situation to develop, but who knows?

[nta16]

All possible but why so intermittent (or once, depending on accuracy of memory) - we need to get the information out of the computers see exactly when and why this happened, I'll happily interrogate them given the chance.  Why is it that the part(s) fails the computer's test yet when you turn the computer off 'n' on again the fails don't remain or return.

 

Another new well, NOSS (new old shed stock) non-dud (so far) P21 bulb was fitted and that might have appeased the computers for now but who knows.

 

[AGFalco]

Test the bulbs before fitting.

If you are not sure on a bulb then fit that bulb in a different place, ( the other working side rear brake )

but then fit the bulb you know works in the original non working side.

 

This way you can work out if it is the bulb, the fitting or the computer.

 

Thanks, AG Falco

 

[nta16]

All good advice.

 

But I wouldn't want to fart and fiddle about removing two Fabia Mk3 rear light units unless I really have to.  With my old car I'd change both bulbs each side of the car and keep the working one that was on the car as a spare.

 

In this case, there wasn't a non-working bulb just a dash warning to say there was.

 

 

41 minutes ago, AGFalco said:

This way you can work out if it is the bulb, the fitting or the computer.

Not always the case, given my Mk4 Cortina story which wouldn't even confirm the bulb.