In the FWIW dept
there should be 2 yellowish 12/10 ga wires that start at the fender relay and feed the GP relay...via the cannon type plug on the right fender.....if yours are burned/jacket soft from heat....you can eliminate them
Just get some 4 ga wire,
couple solder lugs....ones that fit the 5/16" studs on both relay posts---solder and heat shrink the ends and replace that whimpy wiring
If you feel the need for protection, you can get a 250 amp mega fuse and fuse block ---from NAPA for about $25 {
I cannot recall the part #s...been a few weeks ago
}
I ran this set up on my '90 IDI for 4 years at 700 mi a week and never looked back
...without a fuse
Hope this can be of some help