406AC suddenly stop working

[asanka]

Y2001 D9 1.8 petrol 406 Glx .
AC suddenly stops working . its very strange to me because ,AC was working well during the last ride but very next day morning i started the engine and found Ac is not working .just press the button few times but cant here the sound of AC clutch cut in. so checked with a AC guy and he said gas pressure is normal informed me that its may be a wiring problem .he checked the front radiator fan too ,said its not working .
but the engine is not over heating , some times i noticed fan is working hi speed for few seconds like 30 40 seconds like .

i searched the web and found that many owners mentioned its a bsi related problem so changed the bsi relay . but still not working
what could be the problem ?

[asanka]

can any body help me to find a wiring diagram for Air condition .

[steve_earwig]

Hi there, sorry for the pause, it's not something many of us have experience with.

Can I have the build code (RPO/DAM) for your car? 406s changed a lot in 2001 and it makes a big difference to the wiring.

[8Jb9]

I don't know how it is with full-mux cars, but on my semi-mux and many others like it the A/C relay in the BSI burns out. It's possible to replace the relay only with a bit of soldering and a bit of cutting in the BSI-casing to gain access.

Test procedure:
PP2000, engine off -> aircon clutch actuation (should trigger the clutch on and off 5 times, loud metallic clunk).
directly on the compressor: put 12V to the correct pin on the compressor to see if the clutch works, you should hear a loud metallic clunk.

if PP2000 does not trigger the clutch, but the manual trigger does then the first suspect is the BSI relay.

[steve_earwig]

Psst he already changed it

[lozz]

Have you checked the relays for the fans.
iirc..there's two or three behind the grille.

I might be wrong tho.

[asanka]

Hi there, sorry for the pause, it's not something many of us have experience with.

Can I have the build code (RPO/DAM) for your car? 406s changed a lot in 2001 and it makes a big difference to the wiring.

Steve here is the pic of the sticker .sorry im not familiar with this codes.i hope everything you want is in this picture .
[

[asanka]

I don't know how it is with full-mux cars, but on my semi-mux and many others like it the A/C relay in the BSI burns out. It's possible to replace the relay only with a bit of soldering and a bit of cutting in the BSI-casing to gain access.

Test procedure:
PP2000, engine off -> aircon clutch actuation (should trigger the clutch on and off 5 times, loud metallic clunk).
directly on the compressor: put 12V to the correct pin on the compressor to see if the clutch works, you should hear a loud metallic clunk.

if PP2000 does not trigger the clutch, but the manual trigger does then the first suspect is the BSI relay.

thanks Jb .the clutch cut in when i feed 12v directly to compressor .unfortunately i don't have pp2000 tool kit .

[asanka]

Have you checked the relays for the fans.
iirc..there's two or three behind the grille.

I might be wrong tho.

fan low speed is not working . i think normally it would start in low speed when switching on the ac.

i checked the relays all are good ..

[8Jb9]

I think PP2000 is quite important in your case, because you have two possible causes: fan-fault causing the BSI to not engage the AC, or alternatively the relay.

The fan problem is typical, and I currently suffer from the same. As you say, one of the fans go on on high for a few seconds, then stops. I seem to recall someone saying that the problem is the brushes in the fan motors get jammed and loose connection to the rotor.

Try to look through the grille next time, only one will be spinning.

Often the two fans in parallel is OK to keep the engine cool, but when one fails it's impossible to run it at anything other than full speed. Figure out which one of the two fans is faulty by testing the fans individually from the relay-panel in front of the fan assembly (easily accessible if you remove the grille). I think it was on the coupe-forum I received a bunch of good tips on how to wire it up for the testing, it's not that intuitive.


edit - scrap my comments on the BSI-relay, i'm skipping lines today :-)
fan fault it is - although mine works even with a fan fault, so i guess it depends on whether it's the left or right fan that fails.

[asanka]

[quote="8Jb9"]I think PP2000 is quite important in your case, because you have two possible causes: fan-fault causing the BSI to not engage the AC, or alternatively the relay.

The fan problem is typical, and I currently suffer from the same. As you say, one of the fans go on on high for a few seconds, then stops. I seem to recall someone saying that the problem is the brushes in the fan motors get jammed and loose connection to the rotor.....................

my car have only one fan a large single fan like this

[8Jb9]

How does it regulate low speed? Is there some kind of series resistor that might be broken? On the twin-fan models the two fans are used in series for low speed.

[steve_earwig]

The RPO is 08829 (the 89 means it was built at Sochaux, like the majority of 406s), Thu 11 Jan 2001 so definitely a semi-mux. I forgot there are 4 1.8 engines but the diagrams all appear to be the same. I'll add the descriptions in a minute...

[steve_earwig]

It wouldn't let me put the descriptions under the picture so...

BH28 - 28-way passenger fuse panel (I wouldn't take the fuse locations as gospel. Also, be aware that they managed to fit some of there upside-down!)
BM34 - 34-way engine compartment fuse panel.
BH12 - 12-way passenger fuse panel (it's above or below the other one)
1620 : vehicle speed sensor /
8006 : evaporator thermistor (if separate)
6415 : passenger mirror (electric mirror / heated mirror) (external temperature sensor)
1320 - engine ecu
8007 : pressostat
4025 : engine oil temperature sensor + thermal switch
the 90-- stuff is the mux, er, thingy
8030 : passenger compartment air thermistor
8080 : air conditioning ECU
8020 : air conditioning compressor
8010 : coolant temperature unit (/)
8033 : sunshine temperature sender unit
8031 : coolant thermistor
8070 : air inlet flap reduction motor
8065 : mixing flap motor /
8071 : air distribution flap motor (/)
8045 : blower control module (if separate)

Hopefully that'll be of some use to you.

The low speed fan is done by a resistor on these, they do rot out but I don't think they'll stop the air con from at least trying to work.

[asanka]

How does it regulate low speed? Is there some kind of series resistor that might be broken? On the twin-fan models the two fans are used in series for low speed.

there is a resister on the cover of the fan . its fine i already checked . wire number 1592 is the problem its comes from ecu and no power when i ground it fan is working fine