CrazyPete

Good day fellow audi enthusiasts!

My little 1999 early year A4 is giving me the airbag light, something that it has done off and on for 3 years now since I picked up the car used.

On my SAAB 9000, I was able to wiggle my way under the dash and snip a wire that signaled the airbag light to illuminate. I am interested in doing the same. I have no interest in spending the big bucks to start replacing parts and MA is particular about the airbag lights so this seems to be an expedient and final solution.

I tried to go the VAG COM route and got myself an el-cheapo usb interface off ebay..a blue generic looking connector that has OBDII stamped on the top and a green indicator light... and hooked up to the latest Ross-Tech software but could not get it to find the ...my memory is fuzzy here: RT232-usb.. driver. Oh well. It was a borrowed laptop and didnt have the time to troubleshoot and now I dont have it anymore so I'm back to where I started.

Would any of you fine folks have any insight into this?

Thank you in advance and happy motoring!

AudiMick

Why don't you check the connections under the seat first, clean the yellow connectors and zip-tie them together.If not you can install a 4.7kohm shunt resistor inside the plug to fool the controller.

hanshy5

you don't happen to have a write up for the resistor installation do you?

600whpA4

Cutting a wire would actually just keep the air bag light on all the time, this is because the air bag module needs a constant signal from all the air bags to keep the light off.

For the resistor, all you do is loop it between the 2 wires. It basically replaces the OHM resistance that is built into the air bag itself. You can do this by unplugging the air bag and placing the resistor in the 2 spots on the plug or you can do it by splicing or clipping connectors onto the 2 wires just before the plug.


Now depending on the year of your car, the resistor needed can be different. Some of the older B5 A4's need around 5 ohm, while my 2000 needed 2.5 ohm.

CrazyPete

The trouble is.....I cannot reset codes. I have no way of doing it myself. Even if I fix it....which I admit is trivial, the light stays lit and will come back on next time I hit a pothole wrong or...in this case....leave the car sitting for 3 days.

By cutting the wire, I meant the wire that is behind the cluster going up to the actual airbag light. The airbag system can do whatever it wants, I just dont want to be notified of it. Is there any way to trick the signaling system to not tell the cluster that there is a fault? I assume its an LED and not a light bulb.

AudiMick

Remove cluster, remove bulb.

If inspection station notice that the light is not functional feign surprise.

jseklund

Crazypete,
I am on the Cape and have a vag-com. Where are you located?

I know everyone here says they will not pass inspection with ANY dash lights on, but this is just a rumor to the best of my knowledge. Any MIL dash lights on will cause them to fail, but the air bag light should not.

My mom argued this with me for 6 months while her air bag light was on, and they passed her inspection no problem.

If you're nearby and want to meet somewhere, I can at least help with the vag-com if you need.

jseklund

Scratch that - I just checked the RMV and you are correct, they will fail for an airbag light....but you may get lucky!

Reggie

Pete

You should really get a Ross Tech VAG-COM as it will pay for itself with this car. You can reset the signals. I suspect since you have fixed this in the past the connector is bad and based on the previous postings all you need to do is open up the connector - use come electrical contact cleaner and connect -then cable tie the connector and make sure it is out of the way of shoes etc

AudiMick

Very good point.

The fact that the controller is sensing such a low resistance is why this is hit and miss. The condition of the wiring as well as the quality and quantity of the connections within the loom can change the value of the resistor.

Resistors are available with several tolerance from 0.05% to 10%.