Rize RX Throttle Problem


I have a ‘22 Rize RX with Bafang Ultra mid drive. Rode 3000 miles last year with no problems. Got tuneup at LBS before winter. When I took it out first time this spring, everything works fine EXCEPT…. Throttle only works intermittently. As in, throttle engages for about a second, cuts out, engages again, cuts out, etc. Pedal assist fine at all levels and speeds. Have tried plugging/unplugging throttle connectors with no luck. Any ideas on what’s causing or what to try to fix before I take back to shop? Thanks in advance for any help!
After buying a new throttle, removing motor and looking for obvious loose things, to no avail, I discovered that my otherwise great LBS had disconnected the motor shift cutout and never reconnected it. I plugged it back in and, voila, throttle works fine now. Lotta effort for a problem that got fixed by plugging a cable back in.
The cable, with the cutout unit, is located on the derailleur side chainstay, It is under the Velcro wrapped chainstay guard and runs parallel with the motor cable that runs along the same path from the motor to the rear axle. The actual cutout mechanism is a small box in line with its cable. The derailleur cable is run through it so that, when you shift, it detects the shift and momentarily cuts out motor power. But, even if you follow that less than perfect description, the problem is that the connector for this accessory runs forward from the chainstay into the bottom bracket and motor housing. That is where the motor cutout cable connects to the motor. You have to remove the cranks and open up motor to get at the connectors.