Brought a e39 a few questions

[exige92 0]

Hello all.

I'm happy with the e39 540i 1997. I did not pay too much actually got it quite good paying just $4500 for her.

The hassles I have is it needs the pasenger airbag sensor replaced. Have a few months to fix before WOF is due.

I've read about using diodes and resistors to fix wondered if anyone here has gone down that style of fix.

I have heard the sensor does not like big buggers and I'm a shade under 110 kg so I'd hate to fix and unfix.

Only other thing is the driver seat has a failure in the top section that bends the back of the seat.

I need to check the switch but would like to know what its like to replace the motor.

Any help experience would be appreciated.

[turbolizard 38]

Hello all.

I'm happy with the e39 540i 1997. I did not pay too much actually got it quite good paying just $4500 for her.

The hassles I have is it needs the pasenger airbag sensor replaced. Have a few months to fix before WOF is due.

I've read about using diodes and resistors to fix wondered if anyone here has gone down that style of fix.

I have heard the sensor does not like big buggers and I'm a shade under 110 kg so I'd hate to fix and unfix.

Only other thing is the driver seat has a failure in the top section that bends the back of the seat.

I need to check the switch but would like to know what its like to replace the motor.

Any help experience would be appreciated.

The twisted seat is a very common problem and easy to fix. Just search "bmw twisted seat" and you will find a lot of info on methods to fix it. The problem arises from constant twisting of the drive cables which eventually shortens them enough to disengage on one side. The various methods to fix this involve shortening the seat mechanism drive cable sheath to compensate.

One method here...

http://www.m5board.com/vbulletin/e39-m5-e5...eat-repair.html

[Allanw 1071]

IF you do the occupancy sensor bypass, you will probably want to check (INPA?) That it senses the seat is occupied.

On the UK forums, many have discoveredthe eBay bypasses get rid of the light, but DON'T tell the car that there is someone there - so the airbag doesn't go off!

It MUST be set to say there is someone in the seat, otherwise there's no protection.

I don't think it's so much the weight that's the issue, more people kneeling on the seat etc, putting a lot of weight in a small spot.

Personally, I'd fix it and tell people not to kneel on the seat. Even after checking with the software, I'd still be worried the Bypass wouldn't work and have no airbag at accident time

Car sounds like a good deal. 540i's are awesome. Shame there's not more manual ones, Or I'd have waited to find one

[Greg111 13]

DON'T do the bypass for the above reason, it's stupid and dangerous! Replace the sensor and be done with it.

Heavy people do not wear the sensor out, they can wear out all by themselves without anyone sitting on them.

Half the time they get a bad connection at the plug, unplug, plug back in and clear the fault.

[hybrid 1043]

The info on the occupancy sensors and airbag is not quite right above.

If you dont have any one in the passenger seat and have a broken occupancy sensor. The air bag WILL go off.

The sensor is there to tell the car that there is no one in the seat so dont fire the airbag in a crash. It help cut the repair bill down.

When you think about it, why would the airbag system rely on a occupancy sensor that has the potential to wear out and is a big failure point?

All doing the bypass does is make it so both airbags will fire in an acciedent.

The information on dont cut corners is right however, it really should be replaced else you could void your insurance.

[Allanw 1071]

The info on the occupancy sensors and airbag is not quite right above.

If you dont have any one in the passenger seat and have a broken occupancy sensor. The air bag WILL go off.

The sensor is there to tell the car that there is no one in the seat so dont fire the airbag in a crash. It help cut the repair bill down.

But if the sensor bypass unit is telling the car that the sensor is there, but no passenger is there (like some of the eBay ones do) then it won't go off - Dodgy.

[Greg111 13]

But if the sensor bypass unit is telling the car that the sensor is there, but no passenger is there (like some of the eBay ones do) then it won't go off - Dodgy.

Yeah actually if I stopped and read right through your statment I would of said that if the sensor is stuffed then the bags would still deploy on impact as a fail safe, better to have them go off than not, but in saying that, usually when the little red airbag light is on the dash none of the airbags will deploy as there is a permanent fault stored in the control unit.