Compressor and condensor fan starts upas soon as ignition is switched on

[andytat]

Andy

Hi Jonny.

The Singapore car that I spoke to you about 10 days ago or so, when the ignition is switched on,

after a short delay the compressor and condensor fan start running and won't stop until the 

ignition is switched off. The button has no control of the aircon, even though when you 

operate the button the brightness changes. 

If you remember I was unable to access the diagnostics at one stage and to make the

system work I had to bypass the main contactor, even though I had replaced it with a 200 amp

relay of the same type as original.

What do you think the problem could be?

Kind Regards.

[ptseng]

have you check the wiring? back to basic?😀

[mikeL]

Hello!

It seems that the climate control system is constantly receiving a signal to activate the compressor and the condenser fan, regardless of the command from the button.

This could indicate a malfunction in the air conditioning control unit or an electronic fault caused after the intervention with the main contactor replacement.

It's possible that the control relay or control module is stuck in the active state or that the control signal is damaged, especially if a non-standard bypass circuit was used.

[Jonny Retrofit]

If this is an early system that has had it's firmware updated, you may have to swap the signals to be active low.  You can do this using the SIG command in the ECU.