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Electrical guides and mods

Airbag Connector Maintenance

More often than not, air bag fault lights are bought on by the seat side air bags

Modification Details

Why Is My Airbag Light On?

If you have seat side airbags, chances are it is the connection to one of them causing trouble.


Unfortunately, the connectors for the seat side airbags are a bit rubbish. They lock together nicely but aren't waterproof so over a few years the metal connections tarnish which increases the resistance of the connection. Every time you turn the ignition on, the airbag controller checks the resistance of the airbag circuits to ensure that they are OK. The resistance range is fairly tight so eventually the resistance over the tarnished connections brings up an airbag error light.

Coupled with this, extreme cold temperatures will alter the resistance of the circuit as well.

Is That A Problem?

Yes, for 2 reasons. Firstly when there is an airbag error and the airbag light is on, the airbags will not deploy in a crash. Secondly it's not a light you can reset yourself, you have to get smart or a smart specialist to do it as they have to use specialist diagnostic equipment. Obviously if you have a crash where the airbags should have deployed but they don't, the outcome will be worse.

My Airbag Light Is On, What Now?

Follow the guide and take it to smart or a smart specialist to have the error codes deleted.

Preventative Maintenance

Hopefully you are reading this before the airbag light has come on. Keeping on top of this
problem takes a few minutes and can save you a lot of money in diagnostics at a smart garage.
The plan is to keep the airbag connactions clean to reduce the possibility of a fault.

The Underseat Airbag Connector

It is important that the key is out of the ignition and that you do not insert the
key into the ignition until you have sucessfully reconnected all airbag connections. 

It's a nicely multicoloured connector designed to draw attention to itself.
Colours may vary. Pull back the tab, orange on this particular connector.

Once it has moved back with a click, press the back of the tab down.

This lifts the tab allowing you to disconnect the connector.

Get some switch cleaner spray from an electrical shop or online. This is 1 brand sold at Maplin.

Spray the 4 metal contacts in the switch cleaner and wipe them dry.
Quickly connect and disconnect the 2 parts a few times to allow the
cleaning fluid to get in and clear the tarnishing from the contacts.

Leave them disconnected for 60 seconds to allow the cleaner fluid to evaporate
before reconnecting the 2 parts and pushing the locking tab back into place.

Repeat this every 6 to 12 months.

Replacing The Connectors

The other option is to change the connections for something more reliable.
I replaced mine with AMP superseal connections, see the page here.

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