So I've got a rangey in just now which has faults on two out of three blend motors. Simplest solution is to throw a brand new set of genuine motors at it, or so I hoped.
I've bought them, hooked them up, and after resetting the faults... I get faults still. O.o
Far as I can see electrically, the motors are all fine, as are the potentiometers. So I dug a bit further into the pinouts in RAVE, the nanocom HEVAC pdf, and testing voltages with a multimeter. Doing this I discovered an oddity. Two of the three blend motors use red/black as their negative potentiometer voltage reference, as you'd expect based on RAVE. But the right hand potentiometer is mis-wired in all the harnesses I've looked at.
Pin 1 is supposed to be the right hand potentiometer positive voltage reference, and pin 5 the negative. Based on the multimeter, RAVE is correct. But the nanocom manual has them the opposite way round, which you could easily write off as a mistake, but the wires themselves are backwards in the harnesses I've seen.
Can anyone that's got a harness handy have a look and see what colour wires go into pins 1 and 5?
To save you digging in RAVE to figure out which pins that is, if you look at the connector, pin 3 is empty, so pin one is two to the left of the empty slot, and pin five two to the right. Both are on the outside edge of the HEVAC ECU.