406 Stop light and warning tone - A/C?

My 2000 406 HDI has just started flashing the STOP light and sounding
the warning tone when the A/C is on. There is no other indication of
anything wrong at all. Would anyone have any ideas?

TIA

 

Check your cooling fans are working properly.
Mike

 

I'm slightly farther on with this problem - the fan is only coming on
when the high pressure side reaches around 16 bar, and then only for a
few seconds, enough to bring it down to around 10 bar, then the cycle
continues. I don't know if the problem is one, two, or all of the
three relays inside the plastic box, or the resistors that sit up
beside the fan - anyone any ideas? I'm assuming the fan should be on
all the time, is this correct?

TIA

 

You seem to have only one cooling fan, the earlier 406 had 2 and used the
circuit shown on the web site I mentioned.
When air con is on you should have the fan running at slow speed to provide
cooling for the air con rad.
The relays you mention are used in conjunction with the resistors to change
the voltage applied to the fan an hence the speed. They are a notorious
problem, corrosion being the cause. You should be able to prove the
resistors by
1) a resistive check with and OHM meter with the connecting wires removed.
2) with a volt meter connected across the resistors when in circuit you
should see a voltage. You cannot get a volt drop across a resistor unless
the circuit is made and current is being drawn..
3) On my 406 disconnecting the thermostat that feeds the bitrol system
causes the fans to first run at slow speed and then at fast speed. This will
have the same affect as testing in 1 & 2 above but may give you more
confidence in the result
Mike.