I replaced the MFS, the MFS connector, and the flasher relay but the fuse still blows when I use the right blinker or hit the brakes. I unplugged the cruise control plug in front of the master cylinder also. If I take the plug out of the MFS the fuse does not blow.

 

The right rear stop/turn signal circuit is shorted to ground, orange/light blue wire.

Start with inspecting the trailer tow harness, if equipped, for damage as well as the bulb inside the RR lamp housing for a broken filament shorting to the ground or a corroded base.

 

"Plug" ? What plug are you referring to ?

 

The plug for the blinkers and hazards, also I cut the tow package out and the taillight bulbs are new also cleaned the sockets and harness plugs to them

 

Before or after this problem started? If before, then you likely left a bare wire shorted to ground.

In any event, you're going to have to find the short circuit, this isn't an issue where remote advice isn't going to be able to explicitly point you to where the fault is at. It could literally be anywhere between the multi-function switch and the right rear tail light assembly. I've pointed you in the direction you need to go.

 

I’m working my way up from the RR tail light checking everything, will let you know what I find

 

Thank you for pointing me to the orange wire with the blue strip, I couldn’t find the short but I found a spot where I could run a new wire and cut that one out

 

Ok so I had the problem fixed but now the fuse blows when I hit my brakes only, turn signals and hazards work fine only when I press the brake pedal, I changed the brake on/off switch and still blows

 

Then it's not fixed yet.

Go back (again) to the hack job of "I cut the tow package out" and inspect the light green wire for a short to ground.

 

Light green wire has no breaks in it and is no touching anything else

 

Well, the information provided indicates it is shorted to ground. Get your meter out and check it.

 

Found it and replaced the whole back harness so it won’t happen to the other wires over time, thank you for the advice it was very appreciated

 

Good deal! Thanks for following up.

 

To echo projectSHO89..... thanks for the follow up. So many times on this and other sites, the OP never comes back with the solution or viable outcome.

Nice to see it work the way it should (both your F150 electrical and the forum).