T4 and Identifying airbag fault

[RoryRover]

Hi Folks

Just to let you know the car will shortly be going to see BigRuss so I will let you know what the outcome is.

[kissifer1972]

Am pretty certain Russ will find the root of the problem.

I know on mine it is the sensor under the carpet that has got wet.

But, as i say, am sure Russ will find the cause on yours.

Chris

[HarryM1BYT]

Originally Posted by rik007

I have replaced the yellow connectors already and that didnt cure the prob. But perhaps a good test is to remove the seats or at least unplg them and see if the fuse still blows.

Hmmm the bulb idea did seem like a way forward as it would I assume simply have privided a working resistance. But perhaps it could allow more than 5amps to flow. May be also the AirBag circuit is sensetive to current flow.

5amps at 12volts = 60watts .... I think ? i.e. IxV=W ... so I assume a 10watt buld would have drawn about 1amp, way less than the blow rating of the fuse.

What you need to do, is simply wire a bulb across a blown fuse. Then instead of constantly buying new fuses, the lamp lights instead of the fuse blowing. The lamp needs to have a current rating similar to the rating of the fuse, a 10w lamp will be about equivalent to a 1amp fuse - your IxV=W is correct, so use an headlamp bulb. I doubt the actual circuit will draw anything like 5amps though, in a quiescent state - more likely just a few milliamps.

I don't know much about these safety circuits, but on a nomal circuit I would start by unplugging everything,then insert the lamp/fuse in circuit, then reconnect the circuits one at a time until the lamp/fuse lights up full brightness. The last thing you reconnected, is the circuit with the fault on it. If it lights up to full brightness with nothing yet connected, then your fault is on the main harness wiring.

[rik007]

Out of interest .. just been to book my 75 CDT in for an MOT. I was told that AirBag warning lights are allowed to on this year, but as of next year they will consitute an MOT Fail!

Hmm not good in my case where it may be tricky to find the short circuit .. I'd better get looking then!

Rich.

[psicobra]

any news Rory my airbag light was traced to a faulty side impact sensor may be the same in your case however does not account for the blown fuse.

Andy

[yorkster]

Originally Posted by marinabrian

Without a shadow of a doubt, BigRuss is your man I'd say.
Brian

had the same problem myself, mainly when we moved the seat back and forth for me and the mrs driving, initially fiddling with the yellow connector sorted the problem I eventually disconnected the joint and slightly bent the mail terminals so they made a better connection, no problems since

yorkster

[rik007]

Well, had the carpet out yesteday. Quite a faff but its do-able if you have most of a day to do it.

I unplugged all the sensors I could find on the floor and looked as best I could at the loom, but could not see a short anywhere. But the amount of wiring makes it almost impossible to carry out a detailed visual inspection. The floor panel was dry and all looked OK, but whe the igintion was turned on it popped a fuse still.

In the end I disconncted the silver controller box near the handbrake and then tested again. This time the fuse didnt blow BUT there was no current flowing as I assume removing the control box is effrectively braking the curcit.

So ... my question is .. could it possibly be the control box which is at fault? Can they be replaced? Or could it be the steering wheel bag / passenger bag at fault?

Any ideas anyone?

+0
Cheers again Rich

[rik007]

Originally Posted by rik007

Hi, bit of a barge in on this one .. but a question on the back of this thread if I may...

I'm still stuck with the airbag light on and I cant yet find an solution. The 5amp fuse keeps blowing everytime I switch on the ignition. Clearly there is a short somewhere. After a reccoemend; I took the drivers door off and looked at the loom but no joy. I've also repalced the yellow connectors under the seats so I know its not that.

Can a T4 also help me detected where the short might be? Or is it a case of looking for the 'needle in a haystack'?

Next job is to take out the seats, remove the console, remove the carpet and poke around. But am loathed to do that if a T4 could pinpoint it.

Thanks, Rich.

If anyone is interested ... I've just updated the link below which is realted to this thread re AirBag and the Fault Light ...
http://www.the75andztclub.co.uk/foru...ad.php?t=91030


Reagrds, Rich

[rik007]

If interested additional update and solution to my issue on:

http://www.the75andztclub.co.uk/foru...ad.php?t=91030

Rich