Vesku M

SOLVED! Air con clutch polarity need to be HIGH. That explains why a/c clutch and fans had engaged half second after that a/c button was pressed.

Polarity = Low Drive type = Low Side

There is separate A/C amplifier which controls a/c relay, fans, pressure switch, etc.. The a/c amplifier is connected to ecu through these 3 pins AC1 (pin 52 in vipec chart), ACT (pin 63) and ATS (pin 54). It seems to ATS pin is input on a/c amplifier (like ACT pin). I do not dare to try different connections, without better information, because I fear that the a/c amp breaks down.

I don't think that problem is related to ac relay or pressure switch because when I changed back the original ecu a/c worked fine. And when changed back to vipec a/c did not work. Everything else has stayed same when I tested this ecu change.

Checked the pin 63 voltages. - Air con clutch output off / ac button off pin voltage 13.3v - Air con clutch output on / ac button on pin voltage 0v So output is configured ok? What is this third pin named ATS? I do not think that this would be for no reason connected on original ecu?

Both compressor clutch and fans are turning on when a/c button was pressed. But they keep engaged only about half second. In vipec both a/c request input and magnetic clutch output are continously on when a/c button is pressed on. Vipec software and firmware are latest if this information is important.

Air conditioning isn't working with vipec plug-in ecu. I swapped the stock ecu back and all works fine. So the problem must be in vipec. When a/c button is pressed "ac request" input turns on and "aircon clutch" output turns on. Also engine revs drops about 100 rpm for a short time (about half second). Celica ecu has also third pin which has connected to a/c amplifier. Pin Name is ATS (pin 54 in vipec pin chart). What is this pin and Why its not connected to vipec?