I'm so close to figuring this heater issue out, but I've reached another wall.
I've managed to get the display on and functioning (meaning it blows air) for about 5 seconds. When I turn the key to ACC the display turns on and gets bright (like the headlights are off). It then builds the fan speed to high (or whatever speed it was set at when the car was last on) and after that that's when my 5 seconds starts. During that 5 seconds I can do any adjusting of the panel and the blower blows out nice warm air (32°C). However, after 5 seconds the display dims (like the headlights are turned on), the controls stop working (but the display still shows everything) and the blower stops working... Like it almost just dies (almost sputters to a stop). I've now been able to replicate this 4-5 times.
Any ideas? I know for a fact it's not the display module as it does the same exact thing with another single zone display module. Unit is a single zone climate control with single zone ac/heater stuff and the wiring harness is a JDM complete harness and ECU.
Car is a 2005 USDM Legacy GT Wagon with a 2006 JDM RHD conversion (entire wire harness, JDM ECU, JDM EJ20Y motor, RHD dash, and JDM RHD firewall).