My rear running lights dont work even after i changed the bulbs and the fuses

Note the diagram. Left rear turn, the light green wire with orange tracer is voltage. The black wire ground. You need both voltage and ground. Use a test light to check. The voltage for turn signal comes from multifunction switch. As far as the ground, you could try a redundant ground? good luck

About the only thing that affects all three circuits is the multi-function switch on the column.
You would probably need to take a meter or test light and check the circuits there for voltage.

fuse or relay are all the wires correct at the bulb clusters make sure these are fitted correct and the bulbs are the correct type either single or double pole bulbs

Hi David, first check your fuses some have seperate fuses for running lights and headlights, next make sure bulb connections are clean and connecting also check all parking and break lights if 1 is out in rear sometimes they wont work also is your switch on dash or steering colum, either way your coulkd have a faulty switch, HOPe this helps

Have fitted the proper bulbs some have a staggered pin on them only go in one way

Does the brake light in the rear window work? If so, the brake light switch is good. Running lights all work?

Not even the third eye? then the fuse is blown or all the bulbs are out or the brake light switch on the break pedal is bad wire off or broken( it breaks right off the plug then crosses then blows the fuse as the loose broken wire hits the brake pedel arm. Test the break pedal switch first if the third eye doesesnt work either. no power with a test light the fuse is blown or the wire broke ( the wire goes straight to the switch from the fuse and doesnt go anywhere elese. the other wire if hot should light the lights. Most of these wont come out of park without this working as the wire also turns on the park release but some Fords the park release sticks released and Ford made em that way as they didnt like the brake to get out of park law. If the brake lights dont work maybe you ought not be able to get out of park anyway till its fixed. the switch is hot on both wires with the switch pused down and the lights dont still work go after the third eye first if the bulbs are bad change em before you do the rest of the work. on cars with yellow turn signals the brake lights all work on the same wire but red only use three wires, but you didnt say the turn signales didnt work if they work and they are red you r on the way to the turn signal switch as the brake switch powers the turn switch with power then it splites it fot the two lights and adifferent switch circuit for the front hooks them all together for hazard. yellow turns in the back or even separt bulbs can mean blown bulbs ther too its old enought for all the bulbs to fail and the runs still work.

If you put a 2 element bulb in a single bulb elemet socket you would or could destroy the flasher unit. Especially if it is a electronic flasher try replaceing the flasher but get mechanicl flasher they last longer.

You have to check the brake light switch which should be around the brake pedal on the upperside.
Ones located rremove the wires tht go to the switch and jump them by using a piece of wire, thn check if the brake lights come 'on'. If they do , thn its the switch tht may need replacing or even sometimes adjusting inorder to operate.
Hope this helps.

check with a voltmeter at the bulb contacts while someone is hitting the brakes if there is no current. its the wire they rot and a discovery has daisy chained rear lighting. so if the left or is it the righ is bad. then they both wont work. either way if one goes they dont work. its not hard to run a new wire ive done it for car max a dozen times on these vehicles.