Upshift light so this is the later fuse box.
What I would do is upgrade the radiator fan wiring so the relay is on the radiator shroud. Like the MK2s.
Fused right to the battery all in one area, easy to troubleshoot.
There are several wires running back and forth from the relay to the rad fan thermoswitch.
One powers the thermoswitch, then one sends that info back through the firewall to the relay, and one going back out that powers the fan.
Keep one for the manual rad fan switch,.. so when it overheats in rush hour traffic you can just laugh and hit the switch,.. watch the temp go down

.
If you are keeping score:
YOU 1
CAR 0
2 wires left.
and a spare relay spot for a reverse light relay,.. since the reverse light wire goes right past it,..
and you know the lights will burn out the expensive/fragile reverse switch.
The 2-pole switches aren't as spendy or fragile.