say, for the sake of argument, there's a guy wi an old xr4x4, that's been running all year wi the abs warning light on. say he then puts it for mot, it fails for said light. say he then pulls the connection off the light, but the tester then spots it doesn't come on for the 2 secs or so for the bulb test with the ignition. knowing the whole abs system is kaput (£££), how could the warning light be made to come on, then go off after a couple of seconds, looking like all is well? cheers!
Could he not get a replacement ABS lump from a scrap yard?
What would the legality of converting his car to non-ABS be?
think it's the sensors. as it's a theoretical case, no too worried about legalities!
You could remove the sensors AND the ABS pump and then the vehicle is no longer fitted with ABS so it does not have to work. Depending on the system
design this may leave you with a dangerously unstable braking system where the rear wheels will lock first - not good!
[Edited on 30/10/07 by matt_claydon]
if its fitted it must work .....
i had a similar problem with mine, luckily the light stayed off for the whole test.
If its just the sensors won't it be more hassle to 'frig' something that just replace them? Plus you'd then get working ABS.
aye, maybe, but don't want to spend any more, second car, and don't think it'll go through next year...
Or do what the enterprising owner of my last Rover 800 Vitesse did when an ABS sensor went down. He cut the tracks to the ABS lamp in the cluster, and
soldered wires to the oil pressure warning light bulb PCB tracks...
Hey presto, on with the ignition, off when the engine is running...
The MOT test is there for the safety of us and the road users around us. In my opinion it is an absolute no no to try and trick an MOT tester into
thinking something is working fully when it's not - particually when it's something as vital as the brakes.
I really think that the ABS system should be fixed properly. I guess you could remove the whole of the ABS systems and replace with a straight through
system, but could you get the F/R balance right? If the car is designed to have ABS, what's your stopping going to be like without it?
car has driven fine for last year without it. anyway, this is all hypothetical, i wouldn't dream of trying to pull a fast one... and on the previous reply, thought of thatb but should it not go out itslf after a couple of secs? the hypothetical tester is already suspicious of it...
quote:
the hypothetical tester is already suspicious of it...
ha ha! let he who is without sin cast the first stone! just the tight farmer in me... as i say, it'll be the same as last year, and i
didn't run anyone over then...
quote:
Originally posted by robby
aye, maybe, but don't want to spend any more, second car, and don't think it'll go through next year...
shoulda just asked how to make a light come on and off by itself, and not said why... maybe i could start another thread, and the mot police won't spot it?!
As mentioned above, an ABS-equipped vehicle with a faulty systems /can/ be potentially dangerous as the system may be left unbalanced such that the
rear wheels lock before the fronts. When this happens the vehicle will very quickly spin with little possibility of correction from the driver.
Having a failed ABS systems is not the same as driving a non-ABS version of the same car, as these will be fitted with mechanical brake force
distribution valves to lower the pressure to the rear. (The ABS-equipped versions may also have proportioning valves but it's not guaranteed).
quote:
the mot police won't spot it?!
hmm... looks like it's the long way round then... nice to see you're all so concerned with my safety though!
I thought this was going to be about liposuction!
anyway does your abs system have a diagnostic system?
if so, query it as it will tell you the fault.
my volvo told me it was brake sensor, had it replaced, despite what the so called volvo expeerts said, i.,.e telling me it needs new ecu and lamp was
off.
to fudge it, you would need a 555 device set as a timer - in simplest form it could be used to turn on a lamp for a given time after power on. more
fancy could make it flash one or two times.
dunno how easy it is to get to your dahs but that could well be a lot of effort. the time would be better spent looking to find the fault - the
sensors are the usual culprits.
if you fudge, make sure you remove the ciurcuit - then if an accident is casued, who is to say when the ABS failed.
I should really have asked if you travel on the same roads as me prior to respongding.
of course all hypothetical, but if you are driving round Inverness, then there is a hypothetical chance you won't be driving round the Midlands where I'll be alright jack!!!
cheers 02gf74 (?), but started stripping now. (the car, not me) but what's a 555?! and no, there's no much chance of me sliding into either
of you... will let you's know if i'm heading south.
hmmm, if you are askingwhat a 555, then I probably should not be telling you about it.
It is a generic device that with a few external components can be used to product pulses of defined length, oscillators and other time related
stuff.
Without spending too much time on this, one possbile circuit is the one I have shown below, it is the last circuit called 1 second one shot monostable
oscillaotor (try saying that after 4 pints and a madras! 
) .
The switch would be a piece of wire in your case so effectively it is closed when the circuit is powered up.
when power is applied, say igntion is turned on, the lamp would remain on for 1 second.
oh yeah, the one second, one shot, monostable oscillator. how did i no think of that myself? got one under the bench... s'pose i did ask - thanks anyway!
I thought all cars where designed to fail to safe - therefore if the ABS fails the car will handle like a non ABS car with the fronts getting more
stopping power than the rears?
I'm worried now cause one of my ABS sensors is occasionally a little flakey. I've been happy driving the car cause of that assumption (and
the fact i'm used to non ABS cars, i've only had the ABS pump kick in once when i tried decided to try and make it kick in so i knew what it
felt like).
i'm with you on that mike, mine locks the fronts first. i prefer trying it to see what it does, rather than hoping it'll do what it should! hopefully abs sorted tomorrow though... bloody cars...
If its a classic range rover then bin the abs, buy a non abs master cylinder and plumb the pipes in, total cost £85.
This is okay if ABS was an optional extra, so ypu need to look at the really basic models to see if they had ABS.
Regards Mark
a sierra has seat belt reminder light operated by a timming relay.glows for a few seconds when you turn on the ignition.might this do?
quote:
Originally posted by 02GF74
when power is applied, say igntion is turned on, the lamp would remain on for 1 second.
