Hi Craig

I work for Panasonic. Don't know if we talked.
The control voltage for most Sanyo Commercial splits comes off the Power PCB.
I usually use an analogue meter to test U1 and U2 for voltage this is a 12 V pulsed signal which usually shows up as a Jumping needle on an analogue meter.
Most digital meters compensate for voltage fluctuation so it can be difficult to read on a good digital meter.
I would suggest the following (excuse me but cover the stupid obvious first)
1. Check the cable if its shorting to earth or broken conductors or a dead short across the cable.
2. Try the emergency plugs on both the outdoor and indoor PCB. Move the pink and blue control wires
from the blue socket into the brown EMG socket on the indoor and outdoor PCB
3 ensure the open short end terminal resistance pins have the link on the middle and short end.
You will find these above the EMG socket to the left (open-short printed on the PCB in white above these pins.)
4. After above do an address on the system press the AADD button on the out door PCB
If your cable is good
The control is in the emg plug
The open short line is in short position


Do you have voltage on U1 and U2??
have you installed the eeprom on the indoor PCB correctly??
An eeprom has a dot printed on one end and the base has a groove in one side the dot and grove line up>

If above OK the either indoor or outdoor POWER PCB. If you have other units on site
you could swap the power PCB form a different unit to check this.

Contact me on 00353872696043 if you need assistance while on site.
I used to be TECHGUY in here but profile no longer active.
If you cant get me send me a txt I'll get back to you.

Let me know if I can help