Getting a static 88 only on wall remote (error- indoor pcb faulty ,incorrect wiring between indoor and outdoor) no change to wiring been runnng No of years cannot find wiring damage.
U5 (Transmission error indoor to remote)was original error and indoor fan run initially but nothing now then went to 88 nil operation nothing indoor or out,no startup.just green led's
2 wire remote wires look like new.

Both indoor and out door boards have 2 flashing green led's only
Would like to isolation test indoor evaporator fan high and low speed.
Could someone confirm hot wire config for high and low speeds (N, R1,R2,R3 R4) 5wire 240v AC
Checked Internal AC fan for jammed / seized it is very smooth free rotation .
Checked motor windings for resistance and shorts .
Checking each to N Blue to Brown Active 12ohms grey, 17 yellow 19, white 20.3 and no shorts to ground .
capacitor (20mFarads 400v) looks ok

Would also like to isolation test outdoor unit RZP145-DV1
The 2 outdoor DC fans 12v or 22v ? 5 wire plugs to PCB2 and compressor in isolation if possible.
help with hot wiring sorry no manual.

Any suggestions on check process much appreciated.