the brake lights don't work

[Augustin]

Helllo, Good morning !


i'v just realised the bottom brake light do not work. The 3rd brake light works. Turn signal work.
I changed the bulb. Nothing change.
I know there are many post about this subject but i do not understand how to solve it.
I do not know how to start the processus.
Do i have to change the Brake Light Switch or the multifunction switch ? Or anything else ?
Thanks for answer. Sorry for my english.

Thomas

 

[dvdswan]

You're on the right track.

3rd brake light works so your brake switch works. Bulbs are new, so as long as the filament isn't broken those are good.

This leaves a couple of possibilities, wiring to the rear lights, grounding for rear lights, and the brake light sockets. If the turn signals work, then it's a good chance the sockets are good.

Do you have a trailer harness? This can be an issue as well.

 

[Augustin]

This leaves a couple of possibilities, wiring to the rear lights, grounding for rear lights, and the brake light sockets. If the turn signals work, then it's a good chance the sockets are good.

Do you have a trailer harness? This can be an issue as well.

Thanks a lot for quickly answer !
And the possibilitie multifunction switch ?
How can i repair wiring to the rear lights, grounding for rear lights ?
I don't have trailer harness.

Thanks for help !!

Thomas

 

[410Fortune]

Thomas

It’s not likely the multifunction switch because you are dealing with the brake circus and your high mount stop lamp is working when you step on the brakes

So it is either in the wiring or in the actual
Sockets the bulbs plug into

The way it works is a single wire carries the brake signal to the rear of the truck along the drivers frame rail… then the signal splits off into three.. one for drivers tail one for passenger tail and one feed to the trailer wiring adapter

Every explorer has a plug under the back for a trailer wiring harness. From the factory it has a plug in it, but that plug can fall out or the wires behind it deteriorate anyways

Each rear lamp is grounded by a wire to the frame or body as well

You should get under the back of your tru k and identify the wiring in question… do a visual inspection of the harness and its branches

Then do a visual inspection of the sockets where the bulbs plug in, inside the metal fingers that contact the bulb and also the wires going into the sockets and the plastic sockets themselves

Do you have a multimeter or a test light?
The next step would be some testing of the power and grounds to see where the signal is getting lost

 

[Augustin]

Thanks a lot, i will test it.
I saw a lot of treads here that said the MFS is the culprit..
So, it's not the culprit for you ! fine ! (it's important for me because i would have to buy from France so it's expensive...)

 

[J_C]

Wiring diagram attached below