Fixed it

Tom/Barb wrote:
Now what would have made 2 flashers to go at the same time?

Just like when one headlight goes out, the second one isn’t far behind.

Maybe when one relay fails it overloads the second one.

Not so funny things happen with electrical. One time on a trip to Florida my alternator quit changing, I pulled into a shady town in SC ,pulled the alt.rode my bicycle to the NAPA store, they didn't have any but decided to test it,it was fine,re installed it,not charging, put a battery charger on it overnight and headed down the road only to have the battery losing its charge again,r&r the alt again had it tested, charging fine,checked fuses all good,finally had a idea,changed all the fuses with new ones and the problem was solved. As these MHs get older the electronics will corrode.

A short in the turn signal will take out both flashers. The 4-way flasher and the r/l flasher
If it's in the rear it will take out the brake lights as well.
Though the two flashers will not fail at the same time (One fails when you turn and the other when you try the 4-way) they may well fail between the same two inspection/test events.

Last sentence - a short somewhere? Maybe one you fixed along the way hunting this down and didn't even realize at the time.