My March 1992 FD R1 had a 2/3 cooling fans failure last month.
They would only work when the cooling recall grounding wire connector was grounded with my console Max Cooling Switch.
The problem was the two black constant grounded wires for the two fans. Their chassis grounding point is bad.
When I directly grounded them at the two fan connectors, the fans worked properly.
It might be like this problem: https://www.rx7club.com/3rd-generati...ground-992040/
Since I did not want to remove my FMIC with all that trouble, I just tapped into the two wires and ran new grounding wire for them.

 

it seems we are entering the age of unique and irregular failures. 33 years was a long time ago.

we had a z32 come in for non working reverse lights. troubleshot it to the moon and ended up finding the fuse box itself being the problem. whatever is INSIDE the fuse box failed and was keeping the lights from coming on. i moved the circuit and they work like normal now.