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IMPORTANT: enter the case-INsensitive alphabetic (no numbers) code AND WRITE SOME SHORT summary of changes (below) if you are saving changes. (not required for previewing changes). Wiki-spamming is not tolerated, will be removed, so it does NOT even show up in history. Spammers go away now. Visit Preferences to set your user name Summary of change: VemsAudiAan mot55/pin41 '''A/C idle up => voltage divider to protect mch3''' (raw extra ADC mcp3208/3 ). We assumed it is 5V or "12V", and 0V when off. The mch3 has an 1 + 100k / 75k voltage divider (from EGT2 ad597 output), so 68k series with the 100k (in heatshrink coming from mot55/pin41) makes the voltage dividor ratio: * 1 + 168k / 75k * Vdiv=1+168/75 ( = 3.24 ) * V=[5, 12, 16] * V ./ div = 1.54 3.70 4.94 So dividing 5, 12 and 16V to => 1.54V, 3.7V and 4.94V respectively (activation threshold is normally around 0.9 .. 1V). So it should clearly detect on and off condition. (and apparently it does, A/C idle up function became popular). Please edit: What raw voltage do you see in view gauges / raw ADC ( mch3 ) when A/C clutch is on and off ? mswanson: going from memory on my workbench, I had 3.3v when active, and 0v when inactive. this worked with an 'inverted' control strategy on the activation channel in the 1.2.38 firmware settings for idle control AC activation. when measuring the voltage on the car the pin seems to put out somewhere around 10v as opposed to operating voltage of 12-14v. I think this voltage is actually coming from the a/c control head, so its probably regulated down for some reason in the OEM application. Optional: Add document to category: Wiki formatting: * is Bullet list ** Bullet list subentry ... '''Bold''', ---- is horizontal ruler, <code> preformatted text... </code> See wiki editing HELP for tables and other formatting tips and tricks.