Seat Belt.

[barney4444]

When people sit in any of the back seats in my car and forget to fasten the seat belt, I get a warning light and a warning beep, but I have put heavy things on the back seat, shopping bags and even a suitcase, but get no seat belt unfastened warnings, how does it know it's our shopping and not people, they very clever these modern cars, my Ford anglia would never have known..  

[Old_Geezer]

Probably the parcels are too light ?

[bhg481]

Our Volvo complains if there are books on the back seat - we keep our National Trust and English Heritage books there. It also complains if the seat belts are fastened and no-one is sitting in the seat. It's all down to the sensitivity of the sensors used.

[barney4444]

Stuff on back seat is often heavier than our youngest grandchild, but it knows when he's not buckled up! 

[TwoShortPlanks]

It could be about pressure in the seat, and the back of the seat? A person will put pressure on both, but shopping won't? 

I'm just guessing here. 

[Prudie]

I think it must be the pressure point locations. Cars are very clever these days. When I put my cat carrier with cat on passenger seat (I drive a 2 seater) and put the seat belt round it the car thinks it's a little person and de-activates the airbag that side.

[Hopkirk]

Probably AI

[retrocop]

Is it not a sensor in the buckle which activates the light and warning. My female clip of the seatbelt is quite low down between the driving seatand transmission tunnel so I purchased an extention buckle that clips into the original. I could,if so minded, drive around with out the seatbelt fastenened at all and the sensor thinks it is connected betwixt male and female clips.

[davebro3]

from a Toyota forum -

// When my kids sit down, they don’t trigger the seat belt notification. Had the car checked by dealer, who came back saying the minimal weight required for the seat belt sensor to light up is 40 Kg //

[Old_Geezer]

In which case, maybe the parcel doesn't wriggle about ?

 

Or perhaps it's equally heavy at all contact points ?

[Hopkirk]

My car is not so clever. It simply tells me when the rear seat belts aren't fastened so I keep them permanently fastened.

[ladybirder]

You should try driving mine.  It instructs me when to change gear. I mean how would I know I've only been driving for 55 odd years!

[barney4444]

Thanks for all the suggestions and possibles, will have to try and not overthink all these things..  

[Hopkirk]

Those gear change things are often wrong anyway. If you follow them then sometimes the revs are too low and the engine labours.