hello all,
does anyone know what would make the head unit read correct bar pressure of a/c with key on but engine not running,,,,,but when start the car the a/c head unit reads the bar about 1/2 or less of what it should be, thereby not turning on the auxiliary fans??? i have reference voltage at the 3 pole pressure switch at the drier. the look at me wire (blue/red) has voltage when ignition on corresponding to pressure (i suppose because i cant find literature to tell me what the corresponding voltage should be) but as soon as the engine is started this voltage on the blue/red wire on the 3 pole pressure switch goes down to about 1.5 then slowly rises as the pressure rises. what is puzzling is sometimes the fans will work, but not turn on at 156 bar as they should. when does work, they turn on at around 25 bar full speed for short bursts then shut off....any help would be appreciated
thanks

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