MTVR exterior lights issue

[abfisher1798]

Oshkosh MK23. About a year ago, the two yellow running lights on the hood quit working on both sides. Multimeter shows no voltage at the pigtail. This was about a month after I replaced them.
A couple days ago, the drivers side taillight quits working entirely, taillight, turn signal, brake light inoperable. Again, no voltage at the connectors. With the limited technical info, I replaced all the breakers and relays and there was no change.

Also the horn suddenly quit working. Not sure if these are connected or separate issues.

Any guidance is appreciated.

 

[DeMilitarized]

For a start look at all of your primary power and grounds on the truck. Check for corrosion or abrasion there. Just start chasing wires is the best I could tell you. A toner is your best friend.