# Airbag failure.



## erneboy (Feb 8, 2007)

Hello all. I have been getting an intermittent message saying "Airbag Failure, see owners manual".

Ours are IRSI seats on swivels. I am fairly sure this failure has to do with the passengers seat which had to be removed for a repair last year. The mechanic cut the wires to the seat to get it out and joined them again afterwards with round crimp connectors and heat shrink, I have looked at the connections and they seem OK but may not be. 

Before I remove the seat and the connections to re-do them does any one know if a fault there would light the dash warning. I assume this has to do with the seat belt pre-tensioner, Alan.

Edit have turned the passengers airbag off to see of the problem goes away, that should at least tell me which side is faulty.


----------



## poleman (Aug 31, 2008)

I've never heard of cutting SRS wiring to remove components! If crimp connectors have been used then the resistance in the wiring to the control module may have been altered if there is any slight corrosion. 

If you are thinking of repairing the wiring your self DO NOT touch the bare wires as there is enough voltage in your body to trigger any Airbag or seatbelt tensioner. You will need to disconnect the vehicle battery for a period of time before working on the SRS system.


----------



## erneboy (Feb 8, 2007)

Thanks Poleman. Tell me more. 

We were in the van as the mechanic worked on the seat. It is an ISRI seat and had to be removed for repairs. There was no obvious way to disconnect the wiring to allow it's removal so the mechanic cut the wires and joined them again as I described. This was done at an ISRI dealership in Germany so I would have expected them to have known what they were doing which is why I went to an appointed dealership, Alan.


----------



## Stanner (Aug 17, 2006)

I get the same message (well the airbag light comes on) occasionally if the seats are rotated in our Renault based van. 
Jiggling the wires under the seat(s) usually makes it go out if the ignition is turned off and on again. Luckily the computer on that van is one that does a check and reset whenever the ignition is turned on.


----------



## erneboy (Feb 8, 2007)

Mine is the same Stanner. On a journey the fault seems to come and go. I have tried fiddling about with wires to no avail but I am pretty sure that bouncing on the seat can have an effect. Maybe that moves the seat belt, Alan.


----------



## pete4x4 (Dec 20, 2006)

There are two reasons why cables go to seats, one is the pre-tensioner the other is the seat switch.
The seat switch is used to tell you to put your seat belt on and to let the airbag system know that there is a passenger sitting in the seat so it needs to let the passenger airbag off.

I very much doubt that it was the wiring to pre-tensioners as no respected dealer would cut them and then rejoin with crimps. It is more likely the seat switch.

If you are going to remake them, as has already been said disconnect both terminals on the battery and leave for at least an hour then solder the wires together ideally with a gas iron unless you can guarantee that the tip of your iron is ground ie no volts.

Be thankful that you havent an OBD comliant vehicle as the warning lamp would be on permanently.

Airbags and pretensioners are dangerous things  

Pete


----------



## Jezport (Jun 19, 2008)

pete4x4 said:


> There are two reasons why cables go to seats, one is the pre-tensioner the other is the seat switch.
> The seat switch is used to tell you to put your seat belt on and to let the airbag system know that there is a passenger sitting in the seat so it needs to let the passenger airbag off.
> 
> I very much doubt that it was the wiring to pre-tensioners as no respected dealer would cut them and then rejoin with crimps. It is more likely the seat switch.
> ...


This is correct unless the seat has side airbags fitted into it as my car has.


----------



## erneboy (Feb 8, 2007)

Thanks Pete. Maybe you didn't read my original post. All the wires leading to the seat were cut and reconnected. I have described the connections, I can see them. The seat was removed from the vehicle for repairs. I was there when this was done and I drove around without a passengers seat for several days while we waited for the part to come.

I very much appreciate the advice as this is something I have no knowledge of but I can assure you that the facts are as I stated.

Sorry if I appear a little annoyed but I do not understand why anyone would challenge the facts when they are clearly stated, Alan.


----------



## pete4x4 (Dec 20, 2006)

I wasn't really questioning you I was doubting you, there is a difference. :wink: 
Anyway how many wires are involved? 
When the seat was out was the airbag light on all the time or off?
If it was off then your fault is more than likely the seat switch as that is normally open contacts and it would look like no one was sat in the seat.


----------



## erneboy (Feb 8, 2007)

There are three wires Pete. All the time the seat was out the light was lit. Everything looked OK for several months after the seat was refitted, then the light started coming on and going off again as we drive along.

I wondered about a seat switch or the like because it seems to come and go as the passenger moves around in the seat, cornering etc., Alan.


----------



## poleman (Aug 31, 2008)

I would suspect that if the seat sensor was faulty then the seatbelt warning would flash up to tell you to belt up. 

Is it possible that there is a switch to ensure the seat is locked into the travel position as the airbag would be worthless with it facing backwards. Is the seatbelt reel mounted on the seat or door pillar?

The seat belt reel will need two wires if it has a pre tensioner. 

Many SRS modules have a counter to record how long the light has been on for this will need resetting if the light was on whilst the seat was out.

Why was the seat repaired? and what chassis are we talking about?


----------



## erneboy (Feb 8, 2007)

Thanks again Poleman. 

It's a 2008 Fiat. It's an A class van with non-standard seats. The belts are in the seats. As far as I know there is no mechanism for telling the system when the seats are locked in the forward position and there are no seat belt warnings or at least I have never noticed them when moving round a site without a belt.

The light went out when the van was re-started after the seat was re-fitted. I asked the mechanic about re-setting and he said it was not required the system would see the seat.

It was repaired because the cable for adjusting the height had broken, all the adjustments on the seat are mechanical, Alan.


----------



## pete4x4 (Dec 20, 2006)

3 wires would be seat switch and pretensioner. As it's a 2008 Fiat I think a Fiat dealer would be able to scan it and tell you what the fault was but I would remake the connections first. If you clear the fault after 5 restarts the system will clear.
If not thwen a trip to the dealer might be in order.


----------



## poleman (Aug 31, 2008)

If you bounce up and down on the seat and the problem occurs then maybe the wiring in the seat frame has chaffed somewhere and is putting an intermittent fault on.

As Pete4x4 says you may have to get a fault code out of it to progress. I would check the length and routing of the cabling before going down that route. 

Interestingly my 2009 Ducato will not let me go above 5mph before beeping that I'm not wearing my seatbelt, doesn't do it on the passengers seat though.


----------



## erneboy (Feb 8, 2007)

Yes thanks. That sounds like a possibility. The cable which broke did so because it was routed with a 90 degree bend where it attached to the lever. That took it over the frame and making it bind every time it was used. I will look, if I can get the squab off again. I know how it comes off and have removed it a few times but buggered if I can free it today. Thanks again, now I have a few things to try, Alan.


----------



## erneboy (Feb 8, 2007)

A quick update. As you know I fiddled about with the wiring during the last few days and turned the passengers airbag off for a while. Today we did around 30 miles and had no problems. I am beginning to think it's a bad connection and my fiddling has moved and improved it. Or it was the seat switch and moving the squab back and forth trying to remove has cleared the fault at least for now. Finger crossed and thanks for the help. It's not my subject, I am better at mechanical things, Alan.


----------

