I decided to try installing 12v LED bulbs into the 24v lighting system. The turn and reverse lights worked fine for brief durations…. the rear marker lights smoked after about 5 minutes. Not good.
Further investigation determined that many corroded connectors existed and the lighting system in it’s present form was an unlimited supply of headaches and frustrations. While the Hella lights are of high quality, they are 30 years old and are showing the typical abuse that comes with 30 years of being at the back of the bus.
I ordered Maxxima LED units that are sealed, warranted, and unfortunately 12v. This will call for installing step-down transformers in key locations. I expect it to work just fine as the LED’s pull a fraction of the energy (10% to be exact) of the incandescent bulbs.