PUG 406 AirCon Problem

Got my Pug 406 TDI (1.9) checked as far as aircon gas goes today. I thought
it was low as the compressor pump did not seem to be kicking in when I
pressed the aircon button on the dash (bulb on button is OK). Gas pressure
was perfect when checked.

It seems that not only is the compressor pump not kicking in but the
radiotor fan is not coming on as well as it should do when aircon is on.

I'm thinking the fault is probably a relay or pressure switch somewhere
because both the compressor and fan are not working when the aircon is
turned on.

Fan works 100% when just cooling the engine I should add.

Any ideas as to the fault?

 

The fans on this model work in series for low speed when the air con is
switched on and then in parallel to cool the engine at high speed.
First question are both the fans working. If you have only one fan working
first check 3 relays behind grill. Then check wiring loom between relays and
fans This is a design fault and the wiring corrodes badly at the contacts.
The fans are also mounted upside down so water collects and rots the
terminals.
In the wiring loom there is a control relay associated with the bitrol
temperature control system. If there is insufficient cooling this relay will
stop the compressor working.
That will give you some points to check
Mike

 

Had the relays etc checked today and all was pronounced OK. Auto electrician
suspects there may be a fault with the pressure switch and suggested getting
a new one an fitting that. Strange thing is that when I picked it up the
compressor.fan were wirking OK for a short while. Maybe a step closer now.

 

I have a similar problem. Have had engineer around to re-gas Pug 406
HDI "A/C not working when car was brought hole in condensor"
After fitting new a condenser, He started by vacuuming out system,
followed by pressure test “no leaks brilliant” now start car and press
A/C button?
To start compressor, then the problem started no power at compressor.
I was then told I would need an auto electrician to sort out problem
and he was unable to re-gas system. (Still managed £30 call out
charge)
So I looked to the internet for help.
I have removed wiring connector from top of pressostat and shorted
terminal 1 and 2 which starts up my single fan, 1 and 3 makes one of
the relays click, and 1 and 4 seems to do nothing. Have checked and
cleaned all connections to relays by fan and all looks ok.
Is there any way of testing compressor with no gas in system and
without direct 12 volt link.

 

Hi, Pins 1 & 4 should be closed representing gas pressure in system.

Pins 1 & 2 should be normally open, closes when gas pressure too
great
Pins 1 & 3 should be normally open, closes when gas pressure too
great

Voltage should be present at pins 1 & 4.

If gas is present in system and there is no voltage at compressor
clutch terminal there is no point in strapping a voltage there to
prove a point, also on no account strap a voltage there if there is no
gas in system.
The main suspect is the dreaded BSI Built_in Sytems Interface I think
it must contain a relay cos of the current required, but I’ve never
looked at one.
T

 

the fault is BEHIND the relay's,
just pulling out the relay's and test them wil give an OK on the
relay's so the problem seems that theire not getting any suply to do
their job

now take out the whole assembly and inspect it thourougly.
the downside relay has two thin grey wires on it. likely one of them
has gone tits up and coroded of.

to fix it best thing to do is take the wire of, strip it then solder
an extra piece ( like 10 cm or so to it and seal it of with shrink
tube
now do the same for the other one and find yourself the matching size
of terminals that are in the relay holder ( GENTLY pull the old ones
out, its delicat)
if you cant find the ones used in the assembly you might osed the old
ones but i recomend using new ones.

SOLDER the terminals to the wires rather than squeezing them on,
after you pulled the wires through. ( observe polarity! )
gently push them back in, and find yourself a bollte of plastic
sealant
check their working with a volt meter, get someone to switch your a/c
on and off and now replug the relay ( you've cleaned it already) now
check again your a/c ( and fan is kicking in.
after your have done so aply the bottle of sealant and aply plenty
making sure you hit all the spots.
let dry
take some vulcanizing tape and wrap any open laying wires behind the
assembly and put all back in place.

happy motering

 

Thanks, Marc

I'll have a look myself, how do I get to the Relays to start with?