Prius Prime HV battery online detect

Im looking for a wire, preferably not one of the high voltage wires that will go from zero volts, to something higher (12?) when the HV traction battery is on-line (contactors closed). Id like to know if the contractor is closed during "ready mode" and during remote start HVAC mode. Why? Im working on building an enhanced remote start system for this car, that will use a 3rd party remote (long range two way) that will trigger hvac mode. I need to know it worked to send back the confirmation to the fob.

I got this 100% worked out and already running but for a good safe (or unsafe---i work with over 400 vdc at my job) way to detect hvac mode or ready mode has been engaged.

Previously I could just monitor the 12 volt buss, and if it was >13 I could be assured the car was running, but the prime's 12 volt side is very odd, as voltages while "on" can be as low as 11.8 at times. Esp in hvac mode the, and esp more so if plugged in at the time, the 12 volt side is a confusing range of voltages all the time.

 

Ya, I was hoping to tap into coil part of the contractor, but also hoping not to have to dig all the way down to the big battery like that. It might be the only way. I'm working on a possible way to do it by looking for "electrical noise" on the 12-volt buss. This wire would be pure DC, but when the inverter is on, it should have some component of AC on it that I might be able to build a circuit to detect,

 

Anyone know of any wires at either fuse box in the prime that would go "hot" when the big traction battery is on-line? For both ready mode and AC remote start mode?