Saxo Airbag Light

gjb02 · Post by **gjb02** » 28 Jul 2002, 19:39

If you have experienced the dreaded Saxo Airbag warning light flashing away, Answer this question..Have you installed any uprated stereo equipment, that has required a power cable to be run to the boot? If the answer is yes, then I may have the solution to the problem. It is caused by the fields of invisible energy that surround high current(and even low current)cables, called Flux. If a wire or other cable is close enough to the cable carrying the high current, the lines of flux can induce a current in the other wire, this is a form of 'inductive pickup'. The airbag system is designed to need very little current to activate, but if the Control unit senses a current even small, It calls up the flashing fault light. The solution is to route the power cable as far away from the seat belt pre-tensioner wires, situated under the seats, as far as is possible. The seatbelt pre-tensioner wires are another fault producing item, They often get pulled, pushed, and kicked under the seats and this can cause bad connections in the plastic connector. It was suggested to me by a garage that the easiest way to rectify the fault is to cut out the connectors and solder the wires together. Well I removed my power cable from under the carpet altogether, and I havent had a single Airbag warning light since.
Gareth

Dave Burns · Post by **Dave Burns** » 30 Jul 2002, 03:26

Just to throw a spanner or two in here, if there wasn't already a small current going through the airbag and seatbelt tensioner circuit, how does it know when there is a dodgy connection, it's got to send something through, and if it doesn't get it back..........
Yes two conductor's side by side can interfere with each other, but I thought alternating current would need to be involved or, a rapidly switching direct current, since a current would only be induced in the other conductor when the magnetic field break's down, this after all is the principle behind the working's of an ignition coil.
Just my two penneth, any other taker's.
Dave

gjb02 · Post by **gjb02** » 30 Jul 2002, 14:30

[/quote]Hello Dave, what is it they say,"..a little knowledge...". Well it looks that you've got me. I used a limited knowledge to jump to a conclusion as to why my airbag light had stopped flashing when I removed my high current cable from the car. In defence though, I probably could have explained things a little better. For instance although the Airbag system does send a signal around the system to check for open circuits, it will be of a given voltage/current. Should that signal be disrupted by an induced signal of a larger size, the ecu would no doubt regard this as problematic. And dependant on the currents involved it is not neccesary to collapse the fields of flux to to induce a signal in an adjacent wire. Especially that of a tiny signal cable, such as that used in the Airbag system. However the current flowing through the power cable to the stereo system, does fluctuate between negligable and high, dependant on the draw of current required by the amp whilst listening to music. And if I were to turn of my stereo whilst driving, bingo the collapsing field of flux, you spoke of. I've more than likely dug myself further in. But I can only blame myself for posting a half-arsed attempt at a possible reason for spurios Airbag fault lights. It has been over ten years since I studied electronic theory and I now don't use it at all within my work. So like I said,"..a little knowledge." Cheers for putting me right Dave, it helps me to think about things a bit more.<img src=icon_smile_sad.gif border=0 align=middle>
Gareth