I have a 2003 Accord and have experienced the dimming of the lights as I'm driving. This is, of course, means it is difficult to see while driving at night.

A diagnostic test (voltage test) performed at my dealership indicated that I needed a new ELD fuse box.

I found a part number 38255-S5A-003 and was hoping I could simply replace the ELD.
After looking at the fuse box -- it seems this may not be the part for the 2003 Accord.

Do you really have to replace the entire fuse box to fix this problem?

Have someone, first, test the battery and the alternator's voltage regulator. When the car idles, check for 14 to 15 volts between the terminals of the battery. This link may help:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-10.html#post1973613

My understanding is that the Electrical Load Detector (ELD) is not serviceable and the under hood fuse/relay box would need to be replaced. Yes, they are expensive--likely around $250 or more. Consider salvage. Very unusual problem.