Disable seat belt alarm on 2006 Hyundai Sonata

I disabled the annoying chime that sounds when the the driver's seat
belt is unfastened. It required a T10 torx screwdriver to remove the 2
screws holding the cover on the seat belt buckle receptacle. There are
2 wires, one blue and one yellow, that are soldered onto a small piece
of circuit board held in place in the cover. There are 2 circuit
traces on the board and a sliding jumper. When the seat belt is
inserted, the jumper is pushed back to where it no longer shorts the
blue and yellow wires together. When the seat belt is unfastened, the
jumper slides forward and shorts the wires together. The annoying
warning chime sounds when the blue and yellow wires are shorted. All
you need to do is snip one of the wires with a set of dykes. There is
another pair of wires going to another sensor in the seat belt
receptacle. These are buried in the receptacle, unlike the blue and
yellow wires which are in the cover of the receptacle. They are
presumably utilized by the air bag system, and shouldn't be cut. The
blue and yellow wires in the cover only serve to provide the annoying
chime whenever you unfasten your seat belt and can be safely snipped.

 

I'm glad someone finally figured this out. I would have been happy with
the newer programming that Sonata's built after 9/15/05 have, but mine is
truly annoying beyond anything I've ever experienced before. It MAKES me
always wear the seatbelt. The dealer could not do anything for me.

How exactly do you know this? Have you verified this via schematic on the
HMA site? I studied the schematic once myself, but didn't have the time to
devote to make 100% sure I was right. I would really hate to have this
interact with the air bag system someone without my knowledge.

Thanks.
Eric

 

Given that the normal condition while drivng is open it appears the
worst it will do is arm the airbag while parked. That might get
interesting if someone backs into the car at speed.

;-)

 

So you are saying that the airbag isn't armed if you are not wearing
your seatbelt. I don't think so. I would assume there is much more to
control deployment of the airbags. I would hope the key would have to
be in the ignition (and on) at the very minimum. Maybe you would even
have to be in gear as well.

With that said, I'm leaning towards the thinking that this one switch
should have no effect on the airbag, but I am going to try and study the
schematic a bit more before trusting that.

Eric

 

It looks like the blue wire is the ground for the switch. That switch
affects the pretensioner, and the two level discharch of the airbags. How
about the less invasive approach. Find the "dinger", and put a piece of tape
over the hole. You'll still hear it, but it will be much less annoying.

 

No, I said that the most it would do is arm the airbag. It could do a
lot less, like nothing.

 

Already did the tape over the hole thing. In fact, it works fairly well
with the right tape. I used insulating foam tape we have here at work.

Eric

 

I have been in electronics most of my life and I'm not really big on
cutting wires without a schematic. however...where is the damn dinger?? be
glad to cut it loose! or put tape tape tape on it!

 

I don't see a blue wire in the schematic. After looking at the schematic,
I find it possible that the system works the way you describe, but that's
not clear either. From what I've seen, it's possible that what you've
done also tells the air bag computer the seat belt is unbuckled. If
that's the case, it could result in improper or too forceful air bag
inflation in the event of a collision.

My recommendation is to do *nothing* to defeat or fool any of the safety
systems on the vehicle.

Furthermore, if you're driving your vehicle without wearing your seat
belt, you're foolish. That's why the alarm works the way it does-- to
make you put your seat belt on.

 

I couldn't agree more. My issue with the "dinger" is that when I am at a
drive through and NEED to remove my seatbelt to access my wallet, the thing
keeps going and going and going.

I am aware of the fact that this was changed on Sonata's built AFTER
9/15/05, but sadly mine was assembled in August and the computer (according
to my dealer) cannot be updated to reflect the changes made to reduce the
annoyance aspect of the "dinger".

Eric

 

Looking closer at the connector for the seat belt latch, there's switch
outputs there as well as the pretensioner - an explosive. Also, the seat
belt reminder is an output from the SRS module to the body control module.
That means that if you are able to kill the dinger at the seat belt latch,
you are causing the SRS module to believe that the seat belt is buckled when
it's not. It must change some mode of operation of the SRS system - what, I
don't know.

 

The blue and yellow wires and sliding jumper are present in the
driver's seat belt and are not present in the passenger's seat belt.
By experiment I found that the warning chime sounds when the jumper
shorts the wires together and is silent when the jumper is moved to
where it no longer shorts the wires together. Snipping one of the
wires silences the chime.

Does it also affect operation of the air bag system or seat belt
pretensioner? Only Hyundai knows for certain. I surmise that it
doesn't for these reasons:

There are air bags on both sides of the car, but the blue and yellow
wires are only on the driver side.

There is another pair of wires going to some sort of sensor in the seat
belt buckle, and this is on both passenger and driver sides. My
deduction is that that sensor is tied into the safety systems, and the
seat belt warning chime uses a separate sensing mechanism because the
safety regulators expect people to try to disable it and don't want the
operation of the air bag system to be affected when they do so. But
that's just my deduction.

If the air bag system did rely on the blue and yellow wires, snipping
them would cause it to act as if the seat belt was fastened even if it
was not fastened. The air bag system might be designed to deploy more
slowly if the seat belt is fastened. If your seat belt is unfastened
when the air bag deploys, causing it to falsely detect that your seat
belt is fastened could give you less protection.

Incidentally, I asked a Hyundai dealer to silence the chime for me. He
refused, saying it was "safety equipment" and it was "not possible".
If you want to silence that annoying chime, you'll have to do it
yourself.

 

Reasonable enough process of deduction, but when it's relatively easy to
ascertain for certain, why not look at schematics and truly know instead of
suspecting?

 

Very true, but don't we have the right to be foolish? I live in Florida
where there is a mandatory seat belt law but no mandatory helmet law for
motorcyclists, Am I the only one who thinks that is just a bit odd?

Jack Cassidy

 

I had my thinking backward earlier. If this does indeed fool the SRS into
thinking the belt is buckled, the air bag may not deploy or may not deploy
strongly enough to protect the driver.

 

Repair facilities can be on the hook in a lawsuit if they tamper with your
safety equipment. That's why most will refuse to do anything that alters
its operation.