NPP in a box stopped working

[Green95ss]

After months of working properly, my NPP in a box unit has unfortunately stopped responding to commands from the transmitter, and the exhaust valves are stuck in the closed (quiet) position.

I've performed the following troubleshooting steps and believe that the transmitter and/or the receiver unit inside the box is no longer functioning:

1. TRANSMITTER BATTERY GOOD: Replaced battery in transmitter and still no response (light on the remote is functioning when buttons are pressed)

2. VACUUM LINES & EXHAUST ACTUATORS GOOD: Pulled vacuum lines from the actuators and the exhaust valves open up

3. WIRING & "NPP-IN-A-BOX VALVE" GOOD: Removed red 12V and black GND wires from the yellow valve inside the NPP box and valves open up (with audible vacuum release sound from the yellow valve as exhaust actuators open valves)

Any other suggestions on troubleshooting? I've sent an email to nakidparts for their assistance as well.