Ford Fiesta (1995 - 1999) - 99 1.25 Airbag light stays on

Honest John Back Room » Technical matters
View Threaded
Tue 19 Jan 2010 17:47
99 1.25 Airbag light stays on - Gozoman
I have a Ford Fiesta 1.25 Zetec 1999/2000 model Mk 5. Just last week the airbag light came on and now stays on all the time. It doesn't flash; it comes on as usual when I start the car, then goes out as usual then comes back and stays on. Took it to a mechanic mate tonight who did a diagnostic check and it came up as a fault in the airbag module. He also found a voltage drop of almost 4 volts between the battery and the module which he thinks could be causing the airbag module to think it has a fault. I think the battery voltage with the engine running was 14.2 and the voltage at the module was 10.4 or thereabouts. Could this voltage drop be due to a bad earth or a bad connection and if so can anyone suggest where to look? I have already disconnected and reconnected the two yellow connectors under the seats with no effect. I have also disconnected the two plugs from the airbag module behind the centre console and re-connected with no effect. Disconnected battery negative lead and left it off for a while and re-connected but the light is still on! Just had it on another computer and it came up with a module fault and gave the code B1342 but the mechanic says he's not sure if it is the module as they seldom go wrong and the computer sometimes lies. Many thanks for any suggestions.
Reply | Report as offensive | Link
Tue 19 Jan 2010 23:12
99 1.25 Airbag light stays on - bell boy
never known one go faulty
you say codes come up as senser module so if youve checked the senser why not try replacing it with a known unblown one?
im sure my local scrappie would sell me one for £10
no idea what voltages these run at as they go with a big bang when i fire them in bored moments ,i do know i never mess unless the car battery has been off for 20 minutes though
Reply | Report as offensive | Link
Tue 19 Jan 2010 23:41
99 1.25 Airbag light stays on - Gozoman
Thanks for that bell boy. I'm going to do a trawl of the local scrappie's tomorrow. As you say they seldom go wrong so there should be a box full somewhere.
Reply | Report as offensive | Link
Fri 29 Jan 2010 19:21
99 1.25 Airbag light stays on - Gozoman
Managed to pick up a new airbag control module, well new to me as it had been removed from another Mk5 Fiesta. Stripped the old one out this morning and installed the new one. light is still on! Now the rear wiper is starting to play up. It used to stop working altogether and then start again. Now it's working but no longer self parks when you switch it off. Also the tailgate lock no longer opens on the remote. Apparently all these could be connected to the earth which is through the hinges. But surely that couldn't be effecting the airbag in any way, could it?

When I bought the module it also came with the airbag and pre-tensioners so in the morning I'm going to change over the airbag and see if that does anything.

Edited by Dynamic Dave on 30/01/2010 at 00:29

Reply | Report as offensive | Link
Fri 29 Jan 2010 19:37
99 1.25 Airbag light stays on - bell boy
mm very confused now
the airbag change wont make any difference
did you get the steering wheel bit that goes behind the steering wheel and connects on to the yellow cable?
would certainly be worth changing that
im still confused about the reduced voltages though
i wonder if indeed you have a bad earth somewhere causing all these problems?
maybe worth taking out the kick panels and seeing if the earths are all good
Reply | Report as offensive | Link
Sat 30 Jan 2010 04:23
99 1.25 Airbag light stays on - Gozoman
Hi Bell Boy. No I didn't get the clockspring device that fits behind the wheel but it should be worth stripping the airbag off just to check this as I read somewhere about someone finding a broken connection, re-soldering it and curing the problem.

The reduced voltages may not be a problem. I was talking to a mechanic in a local Ford garage today and he said that different devices require different voltages so although he wasn't sure he said it was possible that the 10.4 volt input to the control module was right.

I know I have a bad earth problem effecting the tailgate lock and rear wiper. As far as I know these are all earthed through the tailgate hinges so I'm planning on drifting those out and doing a clean up. Is it possible this could be effecting the airbag system in some way too? Regarding checking other earths I have no idea where to look for these. Can you give me a few ideas? Cheers.
Reply | Report as offensive | Link
Sat 30 Jan 2010 12:35
99 1.25 Airbag light stays on - bell boy
kick panel to the sides of the bulkhead where you put your feet
im sure theres an earth connector under the fuel cut out passenger side

if your tailgate is earthed through the hinges (some have a loom here) then the best cure is a small made up earth strap from tailgate to body next to the hinge

im still curious about the airbag though as its a strange one
Reply | Report as offensive | Link
Sat 30 Jan 2010 12:59
99 1.25 Airbag light stays on - cheddar
I vote clockspring.
Reply | Report as offensive | Link
Fri 20 May 2011 09:08
99 1.25 Airbag light stays on - hunners

Hi, Did you ever get this problem resolved ? I have a Mk5 Fiesta with airbag light on and problems with the rear wiper and tailgate lock. About to start investigating. Was it a faulty earth and if so where abouts ?Cheers

Reply | Report as offensive | Link
Sun 2 Sep 2012 12:52
99 1.25 Airbag light stays on - amichael

+1

Another one here with the exact same problem.

I have bought 2 new replacement modules and I have the same issue. the light is still on. The computer diags is still pointing to the module !I too get intermiitent issues with my rear wipers, but I think it is unrelated it.

Did you ever solve the probelm ?

Reply | Report as offensive | Link

Looking for a garage you can trust? Honest John's Good Garage Guide has thousands of reader recommended garages, plus how-to guides and tips on servicing.

The Good Garage Guide