Hi my airbag light's been on for a while and MOT coming up so need to sort it. It's the driver's side according to the OBD11 scanner. Swapped the sensor inside the door with the passenger side one, but has not made any difference. Looked at the wiring loom going to door and can't see any obvious breaks or chafing in any of the wires. What's the next step? Are there any other sensors that could be faulty? Should I look at the wiring under the seat as well? Cheers for your help with this!

If you could scan the car with VCDS  that would narrow it down, otherwise it’s a needle in a haystack. Wiring under the seat is a good call. Usually yellow wire is related airbag module.

22 minutes ago, spartacus 68 said:

If you could scan the car with VCDS  that would narrow it down, otherwise it’s a needle in a haystack. Wiring under the seat is a good call. Usually yellow wire is related airbag module.

Unfortunately don't have VCDS. If all looks OK under the seat, are there any sensors in the engine bay that could cause the cause the airbag light to come on?

As Richard suggests:- spray contact cleaner on under- seat connectors and give them a wiggle. This should be your first port of call. 

Thanks will do. I should've added that the problem is with the side airbag- that's what the reader said after scanning. I'm thinking it must be to do with the sensor in the door. What I didn't do was remove the larger rubber grommet on the car side, to have a look at the wires- the break may well be hiding in there! Will do that tomorrow. For the side airbag, are there any other sensors?

 

Allesandro.

Fracture of the wiring in the rubber bellows between door and frame is a common problem. I suggest you forget about sensors until you have proved the wiring is intact.

Yes definitely will do today Clifford, cheers!

Thanks for the help all. The usual culprit lived up to its name! Found 3 broken wires when I pulled out the rubber grommet on the body side...one was the yellow sensor switch wire. Connected all up again and erased code with scanner. Airbag light has gone off...result! Booked the MOT 🙂.

Congratulations and thanks for letting us know. It would be worth checking the other doors and boot lid.

1 hour ago, cliffcoggin said:

Congratulations and thanks for letting us know. It would be worth checking the other doors and boot lid.

Cheers!

On 3/7/2026 at 9:53 PM, Bassdon said:

Hi my airbag light's been on for a while and MOT coming up so need to sort it. It's the driver's side according to the OBD11 scanner. Swapped the sensor inside the door with the passenger side one, but has not made any difference. Looked at the wiring loom going to door and can't see any obvious breaks or chafing in any of the wires. What's the next step? Are there any other sensors that could be faulty? Should I look at the wiring under the seat as well? Cheers for your help with this!

1. Remove the Rubber Gaiter: Peel back the rubber boot that covers the wiring loom between the car's A-pillar and the door. You should find a multi-pin connector hidden inside there .

2. Inspect the Wires: Carefully look at the wires as they enter the plastic connector on both the door side and the body side. Look for any that are stretched, kinked, or have frayed/broken copper strands. The break often happens right at the back of the connector .

3. Perform a Continuity Test: This is the definitive test. You will need a multimeter.

   • Disconnect the battery and wait for at least 15 minutes for the airbag system capacitor to discharge. Safety first!

   • Locate the connector you just found in the door hinge.

   • You need to test the specific wires for your side airbag. While wiring colors can vary, the side airbag wires are often yellow and brown. To be 100% sure, you should check the wiring diagram for your specific A6 C8 model year .

   • Set your multimeter to continuity (the setting that beeps).

   • Place one probe on a terminal at the sensor end of the wire (you can access the pins in the sensor's connector inside the door).

   • Place the other probe on the corresponding terminal in the body-side part of the hinge connector. If the wire is good, the multimeter will beep .

   • If it doesn't beep, you have found your broken wire. https://intercarex.by/

Thanks Andy, but this had already been solved a couple of days ago by the suggested method you now detail.

Regards,

Gareth.

Hi Gareth.

I had the same issue with an A3 8P some years ago, had the wiring under the drivers seat checked/renewed, the problem was still there. In the end it was the clock spring in the steering wheel that was dirty. Hope that helps.

Regards Mark