"Air Bag" light, Temp. Gauge + Turbine noise???

I am a member of CPUK no.2482 and I own a Peugeot 405 Estate 1.9D XLD
1996 Turbo.

I have been posting my queries on the official forum because I did not
know that this one existed!

Anyway this is the problem:

Recently as I drive my "Air Bag" light comes on, the Temp. gauge stops
working and now there is a strange turbine like sound under the bonnet
that subsides gradually after switch off. The fuse a 5 amp. in section
5 in the inside fuse box blows but not every time!

The fault corrected itself once?

This time I have driven a couple of hundred miles before it happened
again, any ideas?

Regards, Peter.

 

Addendum: The fan noise is precisely that, the cooling fans are at full
throttle all the time! I have checked through all the fuses both
in-car and under bonnet and they are OK.

 

Not sure that the air bag light and other things are connected. If you have
seat belt pretensioners on that model then the connectors for them under the
front seats are often not too good. Unclip them and reclip with the ignition
OFF.
By cooling fans, I understand the fans in front of the rad. If you have air
con on this model, then there is a Bitron control unit, usually a brown box
just behind the nearside headlight with a multi connector. Unplug this,
spray with WD40 and replug. This cured the fans always on on my slightly
earlier 405. The temp guage is also part of the Bitron circuit.

 

Brian, thankyou for your response, I was beginning to panic, visions of
flat batteries etc!

Pretensioners are not fitted, but I suspect something is amiss under
the steering wheel cover because I had a battle replacing the
instrument cluster some weeks ago, speedo drive wouldnt locate!

As for the fans I will tackle the ideas when I have time off work,
hopefully the Bitron unit is the cause! It will be a relief, it sounds
as if I am clear for take off at traffic lights!

Thankyou again, I will repotrt back in due course.

Regards, Peter.

 

Brian, took your advice, no difference!

Cooling fans still roaring away at full blast!

Any more ideas, I am willing to try anything as long as it doesn't cost
anything?

Regards, Peter.

 

I'm afraid I can't help much more.
Certainly whenever the air con is turned on the cooling fans will run,
that's the way they designed it.
Whether a faulty temp sensor could cause this, I don't know.

 

I'm afraid I can't help much more.

Brian, I think we are at odds here.

By the cooling fans I am referring to the radiator fans.

The "Air Conditioning" is never used because it needs re-gassing and I
am not prepared to pay for the service, I look upon it as a luxury that
is not required anyway!

If I am too hot I open a window, most times the window is open anyway,
even in the winter!

Regards, Peter

 

Certainly if you remove the plug from the brown thermostat sensor, this is
the one controlling the bitrol unit, both fans will run at full speed. Try
cleaning the contacts on this thermostat and its plug.
Mike

 

Mike, this is precisely what I have done, removed all 3 contacts,
sprayed with WD40, reconnected several times to get good contact and
finally screwed up tight with the same result, fans on full blast!

Lost for ideas!

Peter.

 

Follow up:

I have replaced the water temperature sender, removed, cleaned, sprayed
with WD40 the 2 other sender connectors on the cylinder head around the
fuel filter. (What a pain to get to the one behind the filter
housing!)

Result: still the same, cooling fans going full blast!

Anyone any more ideas?

Peter.

 

Replace it will a new one

 

Well, 15 years later, here's the definite answer:

Contrary to the electrical schematics of a 405 ph2 with airco (at least the schematics I have), the airbag and one of the supply-lines of the cooling-fan-control-box (Bitron) share fuse F2, indeed 5 amps. If that fuse is blown, the cooling-fan-control goes into safety mode, which is blowing at full power, this is documented behaviour of the control-box. The cause for the blown fuse, and the airbag-light that comes on, is likely a short-circuit in the clockspring under the steering-wheel. That clockspring transfers 12Volt to the airbag unit. Or the cause is a short-circuit of the airbag-unit itself.
(The airbag-controller is in the steering-wheel too, quite unique design.)

Thank you for sharing your story 15 years back, now I know that my case was not unique!