Airbag warning light - Passenger seat

[David's8]

Originally Posted by moltuae

Done

Attachment 14891

Many thanks Mark!

[David's8]

Just to complicate things, I had a look at the measuring blocks and for Gp 003- "Voltage and Seat Occupancy and Belt Inquiry (front)" for the "Occupied Seat Sensor Passenger Side", the display range is "Child/childseat/light adult/heavy adult/occupied/not occupied/not installed" so the sensor must be measuring the varying resistance of the pressure applied?

[moltuae]

Originally Posted by David's8

the display range is "Child/childseat/light adult/heavy adult/occupied/not occupied/not installed" so the sensor must be measuring the varying resistance of the pressure applied?

Interesting. So the resistance is in some way proportional to weight? I wonder what the weighing mechanism is. Some kind of pressure actuator acting on a potentiometer perhaps?
(apologies if the mechanism has already been mentioned ... I haven't read the entire thread)

Also, does 'small child' briefly become 'heavy adult' under heavy acceleration?

[MikkiJayne]

Wow so it does have variable airbags? That's well ahead of general introduction of that tech

[HPsauce]

Not necessarily, what does the existence of different values in VCDS mean? Is it just that if it sees those values that's what they mean, they may not be used by a D2.
Remember the passenger airbag is a full-size US-spec one designed to stop an adult NOT wearing a seatbelt!

[David's8]

I guess that VCDS will display those values IF the vehicle can produce them and the D2 probably doesnt. VCDS does of course cover the whole range of VAG cars up to the present.

I guess that without getting lost down rabbit holes, the key question is:

1. Shorting out the thigh pad part of the sensor now gives me "seat occupied" indication at all time regardless of whether there is a person in it. Is this a problem?

[HPsauce]

It means the airbag will deploy if it needs to assuming there is someone there.
Least of your worries I would have thought, especially as these are (almost?) all past their original service life anyway so "should" be replaced.

How did you "sort it out" - my shorting method?

[oldnick]

Originally Posted by HPsauce

It means the airbag will deploy if it needs to assuming there is someone there.
Least of your worries I would have thought, especially as these are (almost?) all past their original service life anyway so "should" be replaced.

How did you "sort it out" - my shorting method?

having spent 60 years driving vehicles without airbags I think I may take the risk of not replacing them seeing it would cost a lot more than the car is worth !



andrew , where did david say he had sorted out your methodology ..~I must have missed that

as previously stated ~I would be quite happy to have the airbag 'permanently live ' so to speak

I now have a theory as to how this all works ..that the combined resistance of the 2 pads is sufficient to keep the light off which doesn't happen when the thigh pad fails ......but does when that pad is taken out of the circuit and and the wires from the other are short circuited to make a circuit with that pad alone EXCEPT if the main pad no longer has enough resistance [ anno domini ] when a small resistance has to be introduced into the circuit ; meaning that the airbag is always live with sufficient weight on the seat ?
if anyone has another theory I would be delighted to hear it !
in the meantime I think I shall start cutting wires in the morning ...I always read that you should disconnect the battery before touching anything airbag related ...is this true here ?

phew

[David's8]

Originally Posted by HPsauce

It means the airbag will deploy if it needs to assuming there is someone there.
Least of your worries I would have thought, especially as these are (almost?) all past their original service life anyway so "should" be replaced.

How did you "sort it out" - my shorting method?

Not sure what you mean there Andrew. Did I say that? (My short term memory has an intermittent failure ervy now and again )

[HPsauce]

Originally Posted by David's8

Not sure what you mean there Andrew. Did I say that?

You said "shorting", I misread it as "sorting", oopps!