Replacing seat belt - electrical connectiion problem

[Enjay]

I bought a replacement for my passenger seatbelt from a member on here a little while back (no complaints, all that went very well) but I tried to replace the belt tonight and I've come up with a problem: the electrical connections are different.  The belt looks to be physically the right size (brackets seem the right shape etc) but the wiring on top of the belt is different to what is currently in my car.

The car is a UK-spec PFL.

The new one (and it is a nice spiffy, completely new one) has a short bit of wire on top (just 5 cm or so) with a yellow plastic connector.  It's obviously designed for a nice, quick plug and play replacement.

The one currently in the car has a heavier cast metal structure on the top that the wire comes out of/ goes in to and there is no sign of a connector anything like the one on the replacement one.  I've traced the wire back a few feet but it just disappears inside that black plastic corrugated ducting.

I did toy with cutting the wires and splicing the existing loom to the new belt but I don't want to mess up the electrics on my seat belts or damage the existing belt if things don't work.

Anyone able to help or enlighten me in anyway about this?

Thanks

[Brizee67]

I'm wondering if there's a difference between pfl and fl seats??


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[Call the midlife!]

Are you sure it's not a driver's side belt? Driver's side has a connection for the seatbelt pretentioner so it activates when you "click" the tongue in.
Passenger side has the sensor in the seat pad itself.


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[shnazzle]

Hi Enjay.
If it does turn out to be a driver side one, this means it was ordered incorrectly for me as it is as bought to replace the passenger one.
It is for an FL car, but I had no idea there was a difference. I think I may still have the other 2nd hand one. Send me a pic of this one and I'll compare.
If I still have the other one I'll send it over

[Enjay]

Are you sure it's not a driver's side belt? Driver's side has a connection for the seatbelt pretentioner so it activates when you "click" the tongue in.
Passenger side has the sensor in the seat pad itself.

My existing belt on the passenger side has an electrical connection on it too though.  No idea what it's for.  It's just that the connections are different between the two belts.

This is what the new belt looks like:


My one looks more like this (pic of a driver side one found on ebay). 

Obviously, this is the wrong side but the big cast metal bit on top, and general layout, looks a lot like that.

However, I have just noticed that the above picture has the wire unplugged from the cast metal bit (hole in the middle of the brassy end piece) so I went back and looked at the new one and the short wire can be removed from that, leaving a socket that looks very similar to the hole pictured on the ebay unit above.  So it *might* be possible to unplug the wire from my one, remove the short wire from the new one and plug in the old wire to the new unit.

I was reluctant to try an pull the wire out of the old unit last night because it looked like it was held in with a clip that might have been spring loaded.  So I left it.  I'll have to take another look.

Any idea why these need to have wires in them anyway?  They do not have operating pre-tensioners on them (as far as I can tell).  My MRS (Jap spec) has on the driver's side but this is for the passenger side and for my UK spec MR2.

[Call the midlife!]

Yeah, I'm out, I thought you were referring to the receiving end that fastens to the seat frame. Sorry...


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[shnazzle]

Yup the definitely have pretensioners. That'd the bulk of the assembly.
This is the other one I have

[Enjay]

Yup, that looks much more like what I have.  However, undeterred, I decided to take things apart again and give it another go to see if the connection would work. 

Funny thing is, the connection does fit, but (despite what I said in my first post about things looking right) nothing else does.  i.e. the unit itself does not match up properly with the bolt holes in my car. (I hadn't actually taken the old unit out fully when I tried the new one up against the car the first time, so things looked about right.)

Here are the two units side by side:

As you can probably tell from the picture, the bottom bracket is a bit longer in the new one.  The twist at the bottom is pretty much the correct angle but when the bottom hole is bolted to the car, the little bracket at the top sits about 1cm above the metal cross-member that it is supposed to bolt into.  You can also see that the original top bracket has an angle at the end whereas the new one doesn't.

Not only that, the little top bracket is in the wrong position. 

On the original, it is in the middle (looks slightly off because of the angle of the picture, but it is actually in the centre) whereas the one on the new one is off to one side.

Given that the brackets both bolt on to pretty significant bits of steelwork on the car, I'd be surprised if these mountings had changed position between the PFL and FL versions.  Could it be that this unit is not for a Mk3 at all?

[edit] Just to be clear, I'm not getting at shnazzle here at all.  I'm sure he supplied this in good faith.  It's either that the belts have changed between PFL and FL models or he was supplied an incorrect unit himself and he was unaware of either of these possible problems. [/edit]

[edit2] Either way, I think that it is kind of interesting that the UK spec cars have belts with pre-tensioners and even wires going to them but, as far as I know, the pre-tensioners do not do anything on UK spec cars.  On my import, I can definitely feel the difference when the pre-tensioner is connected. [/edit2]

[Call the midlife!]

Yup, that looks much more like what I have.  However, undeterred, I decided to take things apart again and give it another go to see if the connection would work. 

Funny thing is, the connection does fit, but (despite what I said in my first post about things looking right) nothing else does.  i.e. the unit itself does not match up properly with the bolt holes in my car. (I hadn't actually taken the old unit out fully when I tried the new one up against the car the first time, so things looked about right.)

Here are the two units side by side:

As you can probably tell from the picture, the bottom bracket is a bit longer in the new one.  The twist at the bottom is pretty much the correct angle but when the bottom hole is bolted to the car, the little bracket at the top sits about 1cm above the metal cross-member that it is supposed to bolt into.  You can also see that the original top bracket has an angle at the end whereas the new one doesn't.

Not only that, the little top bracket is in the wrong position. 

On the original, it is in the middle (looks slightly off because of the angle of the picture, but it is actually in the centre) whereas the one on the new one is off to one side.

Given that the brackets both bolt on to pretty significant bits of steelwork on the car, I'd be surprised if these mountings had changed position between the PFL and FL versions.  Could it be that this unit is not for a Mk3 at all?

[edit] Just to be clear, I'm not getting at shnazzle here at all.  I'm sure he supplied this in good faith.  It's either that the belts have changed between PFL and FL models or he was supplied an incorrect unit himself and he was unaware of either of these possible problems. [/edit]

[edit2] Either way, I think that it is kind of interesting that the UK spec cars have belts with pre-tensioners and even wires going to them but, as far as I know, the pre-tensioners do not do anything on UK spec cars.  On my import, I can definitely feel the difference when the pre-tensioner is connected. [/edit2]

To be fair any difference you say you can feel between the two has nothing to do with the pretensioner as it only actually works in the event of a head on collision, in the same way as an airbag.
There's an explosive charge that takes up any slack in the seatbelt in fractions of a second and  pins you in place.


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[Enjay]

Thanks. I think that I have misunderstood what pre-tensioners are then.  I thought it was something to do with a comfort feature on JDM cars.  I've had 2 Import cars (My MR-S and a Eunos Roadster (MX5)).  Both of those have a system where a little of the tension in the belt across the wearers chest is reduced somehow.  It seems to sort of hold the belt ever so slightly slack or something.  It feels a bit weird to me be honest; not massively so, and I got used to it but I'm not sure that I liked it or that it made any real difference to my comfort.  In both cars, it can be disabled via the wiring* and the belts then behave like normal UK spec belts when you do that.


*in the Eunos Roadster, a lot of people disconnect the wire from the seat belt clip socket that causes an annoying buzz if the belt is not being worn.  Doing this also stops the comfort feature working.

In the MR-S, I discovered how to disable the feature by accident when I fitted a UK spec seat to it.  The original JDM seat had more wires than the UK one and when I plugged in the seat (after soldering on a suitable sized UK connector), the comfort feature had stopped working.

[Call the midlife!]

Thanks. I think that I have misunderstood what pre-tensioners are then.  I thought it was something to do with a comfort feature on JDM cars.  I've had 2 Import cars (My MR-S and a Eunos Roadster (MX5)).  Both of those have a system where a little of the tension in the belt across the wearers chest is reduced somehow.  It seems to sort of hold the belt ever so slightly slack or something.  It feels a bit weird to me be honest; not massively so, and I got used to it but I'm not sure that I liked it or that it made any real difference to my comfort.  In both cars, it can be disabled via the wiring* and the belts then behave like normal UK spec belts when you do that.


*in the Eunos Roadster, a lot of people disconnect the wire from the seat belt clip socket that causes an annoying buzz if the belt is not being worn.  Doing this also stops the comfort feature working.

In the MR-S, I discovered how to disable the feature by accident when I fitted a UK spec seat to it.  The original JDM seat had more wires than the UK one and when I plugged in the seat (after soldering on a suitable sized UK connector), the comfort feature had stopped working.

Yeah, that's the connection I thought you were relating to at the start of the post when I assumed the new belt had come complete with the clasp/receiver. It's the connection on the receiver that switches on the driver's comfort feature of the seatbelt when you fasten the seatbelt (I can't remember the official Toyota name for the feature).


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[Enjay]

A bit of additional interest, if I google the number printed on the fabric label at the bottom of the new belt (6042645-P), I get a bunch of links telling me that it is indeed the passenger belt for an MR2 Roadster.  However, they all seem to be ebay links.  The pictures do look like the new belt though.

If I google the number on the old belt (NSB085TL70-P) I also get a bunch of hits relating to MR2s but the links are to car parts companies rather than ebay sellers.

So, I'm still not sure if the age of the vehicle is the issue here or that 6042645-P has been wrongly identified as an MR2 belt (and somehow this has spread across ebay).  I've had a look in a PDF workshop manual and although I couldn't find a part number, the diagrams of the seatbelt are definitely the same style my original belt and not the newer one.


[Driver's side]

Anyway, not to worry.  I'll figure something out.

[shnazzle]

I think the actual Toyota part number is on the box. That'll link up to the parts repository (Toyodiy) for the right year. That should give the answer.
Happy to send the other belt mate. It's just been sitting here.

[shnazzle]

It says there are two parts. 2004 apparently brought in a change.

73220-17151-C0, BLACK, TRIM1*, 2*, 3*, 4* (08/2002 - 01/2004)1€ 200.38

73220-17220-C0, BLACK, TRIM1*, 2*, 3*, 4* (02/2004 - 08/2005)1€ 200.38

Edit:
Answered my own question... It's definitely a 2004+ model.
The pic I put up in my for sale has the part clearly.
And the pre-fl part above it.

[Enjay]

Strange that they made that change.  I can understand them changing to a new belt but the mountings on the car must be in a slightly different place too.  I would have just expected them to have made brackets for the belt to suit the car rather than moving mounting points.  But then, I don't make cars so maybe there is a reason that isn't obvious to me.

I'm happy to swap the belts with you but, if I recall correctly, the price of shipping was almost as much as the very reasonable price that you asked for the belt itself.  Is it worth doing?  I'd also be happy to pass the belt along to anyone who wants it instead, if they want to cover costs.

At the moment, I've swapped the belt from my MRS into the MR2.  It is in better condition.  The reason that I needed a new belt is that the one from the MR2 is showing signs of wear in one place where it rubs against the slot in the plastic trim when the belt is not in use.  It has caused a slight notch in the belt and a small amount of fraying. (Nowhere near bad enough to be unsafe - but MOT issue?)   I'll need to figure out something for the MRS longer term but, currently, plans are that I will probably sell that one on soonish anyway.  My driveway is far too crowded right now.