EMax 25 HST won't start with charge/glow (not sure which) fuse in, but will if removed

[Northaven]

Our tractor experienced a corroded wire leading to the main fuse in the battery compartment. We cut out the bad wire and replaced with butt connectors, 10-guage wire, and electric tape. Tractor started easily during test. We finished putting everything back together and tractor would turn but wouldn't start and I noticed the glow plug indicator wasn't turning on the dash.

We weren't sure which of the two non-main fuses were the glow fuse but we took one out to test and noticed the glow indicator would now come on and the tractor would start easily. We put the fuse back in and the tractor wouldn't start and the glow indicator vanished. What on earth is happening here? Any guidance would be much appreciated!

 

[Roadworthy]

Welcome to TBN. The fuse which loads down your glow plug circuit is obviously powering some additional current carrying circuit enough to drag you voltage down to the point it won't allow the tractor to start. Given the condition of that original wire I suggest a thorough cleaning and tightening of your battery terminals. Look especially for corrosion at the terminal end which may impede current flow. Follow the ground cable to the frame. Clean and tighten there as well. Put a voltmeter on the battery while trying to crank with and without the mystery fuse in place. Record the voltages to see how far it drops. Post that information to solicit fresh guesses.