A seat belt pretensioner is a critical component in the seat belt assembly. If you get into an accident in any modern car, its seat belt system will keep you secure in your seat so that you don’t get jerked forward or fly out of the windshield. Of course, this can only happen if you are obeying the law and actually wearing your seat belt.
If you are wearing your seat belt, the seat belt system has a component called the seat belt pretensioner. The seat belt pretensioner keeps the seat belt locked and pulls it tight during an accident.
See Also: Seat Belt Won’t Retract or Pull Out? (How to Fix)
How a Seat Belt Pretensioner Works
When your vehicle gets into an accident, there is a very sudden deceleration that takes place. There are sensors in your vehicle which detect this sudden deceleration. Once they do, the seat belt pretensioner detonates a small charge which moves a concealed piston in your seat belt system. This charge is similar to what you’d find in the airbag itself.
The piston in the seat belt pretensioner will then quickly turn a spool, causing the seat belt strap (or webbing) to retract. This entire process happens in a fraction of a second. The seat belt strap will basically lose all its slack, making it impossible to move.
Since you are underneath this belt, you stay safely secured in your seat while the impact of the accident occurs.
As you the driver and front passenger stay secured in their seats, the airbag system will deploy its airbags in front of you. The seat belt and airbag systems work together to keep everyone in the front safe.
If you were not wearing your seat belt in an accident, you can’t count on the airbag to save you. The force of the impact would be so strong that you would jerk forward or fly through the front windshield before the airbag could even completely deploy. Some airbags are even designed so they may only deploy if the seatbelt is fastened.
By staying strapped down to your seat, it ensures that your body is positioned directly in front of the airbag so that it can reduce the physical blow as much as possible.
Read also: Airbag Replacement Cost
Seat Belt Pretensioner Replacement Cost
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Seat belt pretensioners are designed to be single use items. You will need to replace your seat belt pretensioner each time you get into an accident. The seat belt pretensioner is not that expensive, especially if you replace it yourself. It’s one of the few parts of an airbag system where a professional mechanic is not necessary.
The replacement cost of a seat belt pretensioner is around $300 to $350. The cost of the part is about $100 to $150 while the cost of the labor is about $150 to $250. You may be able to reduce the labor if you can find a cheap enough mechanic in your area or simply enlist the help of a buddy that likes to work on cars.
Alternatively, there are a few shops around the country that specialize in seat belt pretensioner repair. Simply send them the used pretensioner, they will rebuild it, and then ship it back to you. Repairing or rebuilding the unit will save you some money.
Be careful if you opt to go this route. Seatbelt pretensioners are a safety item like airbags and seat belts, and you need to ensure the pretensioner was repaired correctly if you wish to reuse one.
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I had a dealership replace my pretensioner to resolve a problem with my seatbelt light on the dash. (eventually ended up being a loose connection), dealership scammed me!
I don’t know if they necessarily scammed you. They probably just didn’t do a very thorough diagnostic. Many techs sadly have very poor troubleshooting skills.
A used car I am lookign at has had its pretensioner replaced at 27,xxx miles, but had also had no accidents according to carfax. Why would this have been replaced? Has the car been in an accident that wasn’t reported? This has me also concerned about the airbag system (maybe it was in an accident and airbags may have not been repaired also)
Thanks.
Was there a TSB or recall out on that component?
Could’ve been a lower speed accident, or an accident that wasn’t reported. I don’t know.
Check to make sure your airbag light operates normally. It should illuminate for a couple seconds when you start the vehicle, then turn off. If you don’t see an airbag light, I would be suspicious that they removed the bulb.
The airbag light does flash (self-test) when car is started and turns off as normal.
If you want, do a bit more digging on that year, make, and model to see if there is any documented problems with the original pretensioner.
it’s my understanding and I’ve had this done myself where it’s a federal law that safety equipment on any vehicles is to be replaced at no charge from automotive manufacturers and/or dealers
I’ve never heard that before but I’m interested in learing more if you have a source handy.
I know recalls are free to the customer, but I’m not sure about failures from normal wear and tear or airbags that have deployed. Pretty sure the customer has to pay out of pocket for those.
Good and informative article however neither Parts Geek nor Advance Auto sell Seat Belt Pretensioners. Hummmm……….
You might want to check with a dealership or even ebay.
Dealer? Lol! Yeah, $258.87 plus shipping and that’s for the outermost section of the belt. There’s an online company “repairmysrs” who will repair mine for $67.00 + shipping. Turnaround is 24hrs once received w/lifetime warranty. Because I can’t find a pretensior, care to guess which way I’ll go?
Yeah visiting the dealership isn’t ideal but certain parts can be hard to find. Sounds like you already have it covered, though.
I have a 2016 Crysler Town and County Van 2 of the seat belts have been ruined. I need them replaced what does it cost if a shop fixs the problem?
Probably $200-400, but it’s best to get a quote in your area.
just had a quote to replace driver side belt on toyota avalon 2013. $289 on belt and $120 to install $417.
Watched a video and belt was replaced in about 30 minutes
Glad you were able to get it fixed yourself, Kelsey.