Rapid right turn signal on dash but no right rear turn ligt at all

the flasher unit is out ..needs replaced i believe it is part of the hazard switch on those cars

Sounds like a possible bad ground connection.
Make sure the contacts for the bulb are clean.
Make sure the cround connection is not corroded.

replace the right rear bulb. the quick flashing indicates a bad bulb. it could be a wiring problem to the rear for the signal light that you will have to check out starting at the socket and working forward.

bulb blow in rear or front maybe

make sure both signal lights work front and back if so then there is a signal flasher that will need replacing,it is located at or on the fuse panel under the dash on the drivers side.if you turn on the hazard lights you can find it under the dash and you will know what the signal one looks like also this will allow you to change the correct one and not the hazard flasher that some people tend to do thinking that they changed the right one only they have changed the wrong one.

Most likely a bad multifunction switch (turn signal switch), try wiggling the turn signal lever while it is turned to the left and see ifit ever works.This is extremely common problem on fords,but not the only one, could also be a broken wire ,bad ground or a bad light socket.

check the socket the bulb fits in to make sure it is getting contact

its not the fuse, its either the front or rear lamp is out on that side left or right, or if pulling a trailer you need a heavy-duty flasher unit because this makes the same kind of fast flash problem due to more lamps operated at the same time

The ford explorer sport track. Will have a short either at the plug of the multi-function switch or 6 inches down where the column bends the wires during tilt.

Remove the bulbs one at a time and check for dirt and corrosion at the contacs inside the sockets.The corrosion will cause higher than normal resistence and will make the signal to flash rapidly.As this only happens to the right side only check the right side.