Just got inside from looking at my '89 MH box, almost same as yours in design.
I don't see need to replace, just correct wiring.
I was looking to split my power to rear air to a dedicated plug for dual air at campground and just happened to study wiring in this box to understand.
Mine is stock, and here is your photo with changes needed to be as mine is.
Remove white wire N1 and place over where G1 is now.
Move G1 to the grounding strip.
Place a jumper between the two power supply blocks, as the blue wire shows.
The black wire is correct.
Squint your eyes, and plug it in.