E39 Drivers Airbag
Discussion
The airbag light on my E39 came on just before Xmas. I had it re-set & it was ok for 6 weeks..but is on again.
The MOT passed early April & the garage chap said the MOT law is about to or has now changed & would be a failure. Tbh I was surprised it wasn't already!
Anyway, I heard that the wires, or something..are beneath the drivers seat? And damage commonly occurs by kneeling on the drivers seat thus 'breaking' wires beneath... No idea if this is true or not?
What is the likely cause & fix?
The MOT passed early April & the garage chap said the MOT law is about to or has now changed & would be a failure. Tbh I was surprised it wasn't already!
Anyway, I heard that the wires, or something..are beneath the drivers seat? And damage commonly occurs by kneeling on the drivers seat thus 'breaking' wires beneath... No idea if this is true or not?
What is the likely cause & fix?
Think there are 2 different common problems. One is that there's a mat in the seat base which detects whether somebody is sitting in it or not. I know the passenger side has this, not sure if the driver side does too. Kneeling on the seat can break this mat, which the airbag systems spots and puts the light on. Proper fix is a new mat inside the seat. Think I saw a bodge on the internet of using a resistor to fool it into thinking it's working with somebody sitting in it all the time.
The other problem (which is why my light was on) is the connectors under the seat. My airbag light was because the computer detected a problem with the passenger seatbelt pretensioner (an explosive charge in the seatbelt buckle).
This could be a broken wire where it flexes under the seat, but in the case of mine it was just the connector having slight resistance. I disconnected the battery, plugged and unplugged the connector lots of times having sprayed a bit of switch contact cleaner on it, and put it together again. A mate's got the software to reset the light, and it hasn't come back on since (probably about 6 months now).
The other problem (which is why my light was on) is the connectors under the seat. My airbag light was because the computer detected a problem with the passenger seatbelt pretensioner (an explosive charge in the seatbelt buckle).
This could be a broken wire where it flexes under the seat, but in the case of mine it was just the connector having slight resistance. I disconnected the battery, plugged and unplugged the connector lots of times having sprayed a bit of switch contact cleaner on it, and put it together again. A mate's got the software to reset the light, and it hasn't come back on since (probably about 6 months now).
Did you have a passenger in the car when it came on?
I had a similar issue with my E39 which was triggered by passengers adjusting the position of the seat.
As AJB says the correct fix is to strip the seat and fit a new pad, however I opted for the resistor option, this means if I was to have an accident and I was the only person in the front both airbags would go off rather than just the drivers one.
I bought my resistor kit from these guys and they were very good.
http://stores.ebay.co.uk/the-bmw-workshop-1
Also I am pretty sure that only the passenger seat has the sensor pad.
I had a similar issue with my E39 which was triggered by passengers adjusting the position of the seat.
As AJB says the correct fix is to strip the seat and fit a new pad, however I opted for the resistor option, this means if I was to have an accident and I was the only person in the front both airbags would go off rather than just the drivers one.
I bought my resistor kit from these guys and they were very good.
http://stores.ebay.co.uk/the-bmw-workshop-1
Also I am pretty sure that only the passenger seat has the sensor pad.
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