Can't find my fuse panel

if you don't find anything under the dash to the left of the steering collum
look under the front hatch

Follow your ears.. With engine off and everything quiet turn on the 4 ways and listen for the clicking of the flasher

Question do the TURN SIGNALS work properly? If so then odds are all the bulbs are good.

Now. There are two kinds of flashers.. one the lamps come on the instant you nmove the switch, this type is often used for turn signals

The other there is a brief pause. This is a HEAVY DUTY flasher which can flash 1 lamnp or 10, it does not care how many and that's what you SHOULD have on the 4-ways

Your RV has multiple fuse boxes. One for the house. one (or more) for the chassis. and in mny case one more after market but I know where that is... I put it there

The flasher on a 2004 should support LED lights. Rapid blinking normally indicates that one of the bulbs is out.

check to make sure no one put in LED bulbs this could cause the problem also.