Passenger Airbag - which wire to cut?

1000 PR · August 8, 2011, 21:57

I disconnected the passenger airbag by pulling the plug behind the glovebox but this means the airbag warning light is on all the time so I'm thinking of wiring in a switch so I can easily switch it on and off without messing around with the plug each time but will know when it is definately off because the light on the dashboard is on. (ps. I need to carry fragile loads regularly).

There are just 2 wires leading to the plug so will it make any difference which I cut and use for the switch?

Steve Green · August 8, 2011, 22:10

Page RS 50 of my manual talks about a deactivation switch in the glove box. But that might be a red herring.

frogger · August 8, 2011, 22:42

The manual is for the US market, where there was a switch... but it shows it can be done.

There has been some discussion on this before I think, but don't recall that it ever reached a conclusion.
In the past this topic has come up with reference to child seats.
If I had harnesses fitted instead of (not in addition to seat belts I would certainly be tempted to disable passenger + driver.

With reference to your Q - Breaking one will probably do the job, but personally I would go for a DPST (double pole single throw) switch and break the connections in both wires.

Be aware though that there is such a thing as a faulty switch, and they're more likely to fail than a standard airbag electrical connector.
If left undeclared there's always the chance your insurance would try and find a way to make it count against you if you were ever involved in a serious claim, regardless of the effect it actually had on the claim.

As an aside... Should you find yourself in a airbag activation situation, would your 'fragile load' not be just as damaged by the er, crash? lol

Anonymous · August 8, 2011, 22:55

it was discussed but noone wanted to be a guinea pig s:lol: :lol: s:lol:

as for switch the air bag only goes off if there is a charge across it ie one live one negative wire. a switch on either will disable it but as you said it will put the light on and possibly disable the whole system.

as for the system knowing its not there it must put a very small charge in the system to see if its connected. maybe a two way switch one connecting the two wires so it works and then switch the other way to just connect the two wires so it bypasses the airbag.

bigwillcv36 · August 9, 2011, 01:12

CUT THE RED WIRE! NO, THE BLUE... NO, NOT THAT ONE!!!
Sorry, bit of a 70s disaster movie flashback s:oops: :oops: s:oops:

Steve Green · August 9, 2011, 10:22

I was just looking at my manual again. It probably is for a US car as has been said, but....

The wiring diagram shows the switch to isolate the passsenger airbag. From the diagram the switch has three functions.
1. It has an independant circuit to turn on the warning light that probably does not exist in a UK car.

2. It isolates the trigger signal from the control unit disabling the airbag, this will set the standard UK warning light flashing but......
3. It then fools the control unit into thinking the airbag is still connected. Under normal service it look as as though a very small current passes through the airbag so the switch internals replicate the resistance the control unit would expect to see. The manual says 2.4 ohms.

If you really want to isolate the passenger airbag, and there are good legal reasons in the UK not to, I would first track down a replacement switch from the US. But replacing the airbag with a 2.4 ohm resistor would achieve the correct result.

Obviously I have great reservations, make no reccomendations, and provide this information for discussion purposes only.

1000 PR · August 18, 2011, 09:09

I guess the biggest concern then about simply pulling the plug is that the whole system might be disabled.

Is there not a seperate plug to disconnect the driver's airbag?

Steve Green · August 18, 2011, 09:34

There is a plug to enable removal of the airbag from the steering wheel spiral cable assembly.
Just what happens to the rest of the system when you disconnect it I have no idea.
Unless you plan on fitting an aftermarket steering wheel, why would you want to remove a vital piece of safety equipment that would invalidate your insurance?
I was kind of with you on the passenger airbag, but the drivers one is a step too far IMHO.