by jpsmit » Thu Mar 24, 2016 2:47 pm
Not exactly sure how the HC compared to the GT in terms of wiring, though considering the era, they can't be far off. I have been working on my wire harness for a couple of weeks now and the notion of a 50 amp fuse terrifies me! Those wires mostly seem undersized already.
Every wire harness I have (and I think I have 4) had the wire from the alternator to the ammeter burned and frayed at exactly the same spot. Others on the board assure me that it is where the harness is clipped to the oil pan - the wire eventually wears through and grounds on the engine. Assuming there is some similar arrangement on yours, this would I think account for both the loss of charging ability (light goes on) and fuse blowing (grounding).
In terms of the fan etc, this would be a really good time to add a relay or two - they are easy and cheap insurance and will lower the draw on the whole harness.