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Peugeot 406 (1996 - 1998) - 1998 2.0 F21 Circuit Power  
1998 2.0 F21 Circuit Power - BazC
Hi,

Wonder if anyone has seen this before ...

The first symptom was that the digital aircon panel appear to die electrically. I replaced the panel and that was not the problem.

After lots of sniffing around with a voltmeter, I found that the entire circuit (fed by fuse F21) is unpowered. The book lists this circuit as Air Conditioning and Ventilation.

Does anyone know what would cause this (assuming no wiring fault)?
Maybe a compressor problem or blower control?

Please help

Tags: technical issues used cars air conditioning small cars

1998 2.0 F21 Circuit Power - Screwloose

Is fuse 21 live at key-on?
1998 2.0 F21 Circuit Power - BazC
Hi Screwloose,

No, with key on (and engine running) the F21 circuit is unpowered.
I'm wondering if there's something like a blower control fault if it removes power to the circuit ...
1998 2.0 F21 Circuit Power - Screwloose
Baz

First; double-check your fuse layout with the handbook. There are three different makes of fusebox used on these and they also vary year-by-year. Yours should be the 97-99 box in which fuse 21 [10 amp] in the dashboard fusebox is for the A/C - but trust nothing about PSA fuse positions.

If both contacts in the fusebox for that fuse are dead; then find the wire coded KK2 coming from one output of the ignition switch [fusebox plug H - pin 5A] and see if that is live key-on. If not; check the same wire code leaving the ignition switch.
1998 2.0 F21 Circuit Power - BazC
Hi Screwloose,

Can you just confirm that plug H in the fusebox is the 'diagnostic port' on the right hand side. How are the pins laid out ?

Wire KK2 doesn't appear to be on the wiring harness below the steering colum - I guess that I need to go right into the ignition barrel itself.

For what it's worth, KK1 is live at key-on. F21 is dead on both sides of the fuse. Wire 8002 (on the back of the aircon panel) is showing zero volts.

Thanks again

Barry
1998 2.0 F21 Circuit Power - Screwloose
Baz

Plug H is one of the multi-plugs, not the diag socket. The feed to fuse 21 is straight from key position 1 of the ign switch vis wire KK2. KK1 is the main ignition switch output on position 2.

This is looking very like a ign switch failure.

If memory serves; there should be 5[6?] wires on a petrol switch? Two are permanently live; [BM 1 + 2] one is the starter; [wire 100?] one is KK1; so you want the other one - which should be live when the key is in position 1 and 2. It's number will only appear downstram of the ign switch plug.

1998 2.0 F21 Circuit Power - BazC
Screwloose,

I think you might be right about the Ignition Switch!

There are 6 wires:

Brown Connector (BM2-White & KK1-White)
Grey Connector (AA1-White & CC01-Yellow)
Black Connector (BM1-Red & *100-Red)

I cannot find any wire with KK2 on it - maybe its the *100 Red wire?

Anyway, here's what happens with different key positions:

Ignition Off
AA1 zero
CC01 zero
KK1 zero
BM2 12v
BM1 12v

Position 1
AA1 12v
CC01 zero
KK1 zero
BM2 12v
BM1 12v

Position 2
AA1 12v
CC01 12v
KK1 zero
BM2 12v
BM1 12v

KK1 is always dead !

I am thinking about feeding the KK1 line with 12v from the battery (with a fuse in between) to try and prove that the circuit still works ... what do you think?

Thanks again

Barry
1998 2.0 F21 Circuit Power - BazC
Screwloose,

[sorry ... an updated version of the one above]

I think you might be right about the Ignition Switch!

There are 6 wires:

Brown Connector (BM2-White & KK1-White)
Grey Connector (AA1-White & CC01-Yellow)
Black Connector (BM1-Red & *100-Red)

I cannot find any wire with KK2 on it - maybe its the *100 Red wire?

Anyway, here's what happens with different key positions:

Ignition Off
AA1 zero
CC01 zero
KK1 zero
BM2 12v
BM1 12v
*100 zero

Position 1
AA1 12v
CC01 zero
KK1 zero
BM2 12v
BM1 12v
*100 zero

Position 2
AA1 12v
CC01 12v
KK1 zero
BM2 12v
BM1 12v
*100 zero

KK1 is always dead !
*100 only shows 12v when cranked over into the start postion.

Interestingly, There was an intermittent fault with this about 6 months ago. Sometimes it would work and sometimes not, but switching the ignition off then on usually cured the problem.

I am thinking about feeding the KK1 line with 12v from the battery (with a fuse in between) to try and prove that the circuit still works ... what do you think?

Thanks again

Barry
1998 2.0 F21 Circuit Power - BazC
Hi Screwloose,

I just connected the battery directly (with an extension lead) to the KK1 wire just downstream on the ignition barrel ... ALL WORKED PERFECTLY !!

I guess this proves your theory that its the ignition switch?
1998 2.0 F21 Circuit Power - Screwloose
Baz

Change the switch - or, if you can solder well, fit a relay to link BM1 to KK1 when CC01 is live. [I've done dozens of those on the small PSA cars.]

The CC code is a later main ignition circuit designation - looks like they mixed-and-matched the two systems on yours and thus swapped the KK lines - don't you just love French wiring.
1998 2.0 F21 Circuit Power - BazC
Screwloose,

Not sure I'd be up to soldering in a relay (I've only just managed to blag my way this far!). Where might I get my hands on a relay? would I end up just blowing lots of fuses with a double feed on the BM1 line?

Is the ignition switch a big deal to change?
Do I need a mina dealer to do it?

Thanks again for all your help ... I'd never have gotten this far
1998 2.0 F21 Circuit Power - Screwloose
Baz

Any standard 4-pin mini-cube 40amp relay will do. [About a fiver.] Both circuits fed off BM1 anyway. BM2 feeds AA1.

Fitting a new switch isn't hard - just a bit fiddly; a Haynes would be a boon.

Depending on the make of the lock and switch assy; [Neiman?] you might have key-chip issues. Some keys have a detatchable head [tiny, hidden, screw] and you swap them on to the replacement lock's key-blades - some locks need their solid keys' chips re-matching to the immobilizer by a dealer.

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