2013 Prius Plus DTC P0A84

Hello,
I am from Norway and new to this forum.

My wife own a 2013 Prius Plus (European model v?) that has almost 433000 kilometers (269000 miles) on the odometer but still running strong

It is well maintained and has been a blessing for us for many years - more or less problem free for all these miles (except for new head gasket on warranty, replaced the water pump once and cleaning the EGR system).

Now the hybrid warning light is on constantly, and has been so for a few months.
The DTC is P0A84.
The hybrid battery blower sits under the passenger (right) seat on these and I have located corrotion in the connector to this blower (I do not think the blower runs at all).
I have re-wired the blower through a new connector but the fault is there still.
When erasing the DTC the warning light goes out but after just some seconds it is back on again so I have obviously not located the problem.

I have been reading multiple threads on this forum regarding the same problem but mostly for older Prius models and not for the Plus or v models and I'm a bit stuck on how to proceed to locate and solve this problem.

Any hints and tips is highly appreciated.

Thanks,
Lars