Golf mk7 Electric Handbrake Won’t Release

[Spydaman]

My Son who lives in Sweden has a mk7 Golf where the handbrake one side won’t release. He lives in the middle of nowhere so can’t just take it to a garage. He hasn’t got the VW service tool to put the brakes in service mode but has managed to get the caliper off. I’ve told him to remove the motor and power it remotely to see if it’s the motor or wiring to it. He’s also going to clean and lube everything to make sure it operates smoothly.
Any other suggestions or is it a replacement calliper or motor?