The snag is the same Lucas window switches used were also used without relays on the likes of the Stag, so you'd need quite a lot of current to keep them clean. Luckily, not a hard job to clean them once in a while.
On the Meriva ECU [1] it was just bad connections between the two multipole plugs and the PCB. The problem was the PCB was ceramic and the tracks ally and so the wires had to be 'welded' onto the tracks somehow.
On daughters van diesel fuel injector pump controller it was a MOSFET that controlled one of the solenoids that had gone (known / common fault). That was repaired by the same people who did the Meriva ECU but failed within 3 minutes when put on the Bosch test jig. They repaired it again (FOC) and again it worked initially before failing a few minutes later. With this all costing time and money we were then given the option of a cheaper FI pump (with controller) so we went for that.
As an aside, we gave the pump electronics back to the repairers (with the thought of keeping is as a spare as it was still coded to her van) but when they went to repair it, they couldn't so offered us all our money back. Not knowing if it was bad electronics in the first place or the pump killing the electronics, we said we would accept a 50% refund (that seemed fair to us as they had done quite a bit of work on it and typically had no issues with their repairs ('bread and butter' unit etc)).
An ex TV engineer mate used to repair ECU's for his brothers garage and 'often' it was just a minor component (like a resistor) that was required. That didn't stop them charging 50% of a new unit though. ;-(
Cheers, T i m
[1] The fault was intermittent but fairly predictable.It would always start from cold or restart from very hot. It never cut out once running (although the instruments would). It would rarely restart from warm unless left to cool fully.
Then, after a couple of months of this, one day it wouldn't even start from cold and then I found by heating the ECU with a hot air gun, it would start fine. Once I had repeated this test over 3 (cold) mornings I was happy it was the ECU and removed it, the Body Control Module, Ignition / immobiliser module and the instruments and took them and an ignition key over to the repairers. That way they could test / repair my ECU and I wouldn't have to get anything re-coded. ;-)
When we replaced the indicator switch unit on the Meriva and the wiper switch module on the Connect I noticed on both how fine the wires were so imagined they were mostly just 'signal' wires to drive other things.
The advantage of allowing something else to do the work (as has been mentioned elsewhere) is they can then do other / more things, like substitute a failed sidelight with a reduced power brake light and / or warn you when a lamp has failed.
Also things like put the rear wiper on if only the fronts are on and then you go in reverse or re-lock the car if you only unlock it but don't then put the key in the ignition (plus loads more). ;-)
Cheers, T i m
(*ITYM tail-light?)
The big advantage to this approach is that manufacturers can add features to each trim level to up-sell, with just software changes, at minimal cost to themselves.
Chris
I've never seen that. How were the components connected to it? All the ones I've ever seen have copper contacts.
Good question(s) but I can't answer I'm afraid. I think they may have mentioned 'ultrasonic welding' but I might have mis remembered.
This guy seems to mention 'aluminium solder' (around 4:10-)
I did indeed (although whilst sidelights may technically refer to the front low wattage lights, I think we also generally refer to all such marker lights (front and back) as side lights? Except we don't include 'side marker lights' in that). ;-)
Ah, crafty.
I think I've seen mention of such on the various vehicle OBD type software where users enable 'value added' stuff themselves and for free. ;-)
Cheers, T i m
Quite!
I guess if all you do is run at an average speed of 10mph from your town house to the local supermarket and back once a week, then it probably doesn't matter what mix_n_match combination of tyre makes, models and tread patterns you are running.
If OTOH you regularly travel a resonable number of miles at reasonable speeds and in all conditions, then a decent set of matched / branded tyres would probably be a good idea (for everyone). ;-)
Cheers, T i m
I remember hearing that that was what Jaguar did on the Mk. 11. The wiring was there, it just wasn't connected on the lower-spec. model.
40s Morris Minors had two tail lights, but the NS one a dummy. ;-)
Ultrasonic bonding of aluminium is the usual way of attaching aluminium wires to aluminium pads.
You can get tine/zinc alloys that solder just about any solderable alloy including aluminium.
A proprietary make is Alusol but is expensive and is a tin/silver/lead alloy.
Ah, good, I didn't get it wrong then. ;-)
Interesting.
Looking at the bit in the video where it shows the connections under a microscope, I think getting it professionally repaired was money well spent. ;-)
From memory I think there were 64 connections on each of the two plugs to the ECU (albeit that only a few of them had gone at that point) but I think they said they stripped and re-connected all of them?
Cheers, T i m
Yehbut are you saying the components - resistors, caps, ICs etc have ally wires or pads? Odd I've never seen them on sale anywhere.
I really can't think why you'd make a relatively expensive part like a car ECU with ally tracks when even the cheapest throwaway electronics still use copper. Ally isn't a good conductor and you'd need to make the tracks much larger too.
on 24/10/2017, Dave Plowman (News) supposed :
I would suspect the tracks are tinned copper and the OP has mistaken tinned copper for alloy.
Or someone was pulling his thingie.
Many ECUs are Hybrids. Their main advantage is they are 'generally' more reliable and rugged.
If you think about it, the video showed a lead breaking through fatigue. With lead free solder and its issues I'm not surprised that hybrid are commonly used under the hood.
Looks like a ceramic PCB with wires being bonded (to what looks like what could be ally tracks) without solder or smoke though?
Cheers, T i m
It's not what is generally called a PCB.
It's a massive hybrid ceramic chip carrier with more than one chip and a lot of extra bits - multi chip module. Chips and transistors are bonded on the carrier and the lead-outs that in a normal chip would bond on the chip legs are bonded on the chip carrier.
Ok, but for what I believe were the purposes here (the 'board' inside an ECU'), that is what we are referring to.
That is a good description of what I actually saw in the video, yes. ;-)
Makes sense.
I saw plenty of those when working for BT (bench electronic repair), often in Modulators and Demodulators (they were discrete rack mount modules in the old 300 baud MoDems). ;-)
So OOI, differentiates one of those from straight LSI when a single chip effectively contains many independent logic modules (ignoring the actual transistors etc)?
Fascinating. I love looking at stuff under my USB microscope. It's like another world opens up. ;-)
I think they key word there Peter is 'now'. The Meriva is over 13 years old and probably built reasonably 'conservatively' (comparatively basic EuroBox etc) at that.
The irony of the fault in our case was that it was (partly at least) on the actual data / OBD bus so when it occurred, the car carried on running but you couldn't monitor it doing so. ;-)
When the fault cut in whilst driving, the passenger could tell the instruments to read 30 mph (OpCom OBD tool on laptop) when it was otherwise showing zero and the speed output from the ECU also showed zero (or something like that). ;-)
When the fault changed / worsened it must have also affected the immobiliser circuitry as it wouldn't stop when running but wouldn't restart (when warm).
Cheers, T i m
The most likely things to fail on any engine management system is an external sensor. Just whether the built in diagnostics will tell you which one every time reliably is the moot point.
Fault finding with electronics needs not only a good basic knowledge, but experience of the particular device too (or pretty well unlimited time). Not easy to find anyone with both.
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