94 Ford Ranger no left or right brake light

[Boostaddict91]

I've got a 94 ranger that recently the brake lights stopped working, the third brake light still works fine as does all the other lights in the rear. All fuses and bulbs check out good. This is the style that has the turn and brake as seperate bulbs and I have searched but cannot find anything similar with my style truck. Looking for advice.

 

[RonD]

Welcome to TRS

Yes, you have a 3-wire tail light system in a 1994

1 brake wire and 2 turn signal wires at the tail lights
(Also a Park light wire and backup light wire)

If someone added a trailer light plug-in that will often be the problem, the splice has corroded or broken the wire

Look under drivers side rear corner of bed, for the wires coming from the cab, in the frame rail
solid Light Green wire is the brake light wire that splits and goes to both rear brake light bulbs

It is no longer connected to either bulb

The 3rd brake light wire is in the cab so if 3rd light is working then fuse and brake switch are working
The light green wire is not connected to rear bulbs

There is also a light green/orange stripe wire, thats for turn signal NOT brake light, you want to find the solid light green wire, no stripe
If park lights work its not a Ground issue

 

[Boostaddict91]

Thanks! I crawled under there this morning and it had a trailer harness jumper in between the two trucks plugs by the trailer hitch. I unplugged this and plugged the two truck connecters back together and now the brake lights work! Guess the trailer thing went bad.

 

[RonD]

Good stuff

Yes, trailer light wiring can be the source of several vehicle light problems

 

[Boostaddict91]

So now I'm back to square one no brake lights? Tested them before unplugging that jumper and they didnt work. Unplugged the jumper and then connected the two sides together and they worked. Just noticed pulling in the driveway they arent working again. Third brake light is working and the parking lights still work.... I'm clueless here.

 

[Uncle Gump]

Bad connection at the tail lamp plug.

 

[Boostaddict91]

That would cause both to not work?

 

[Uncle Gump]

If you have separate turn signal bulbs... then yes. The brake wire splits in the tail lamp harness.

You will probably see a dirty green connection in that plug.

 

[Boostaddict91]

Yes I have the 3 bulb style separate turn signals from the brakes.

 

[Boostaddict91]

Cleaned up the connectors they werent really dirty or corroded and still nothing. The only thing I can think is somewhere between the switch and the tail lights the wire is broken.

 

[RonD]

Bad wire would have to be in the connector or it wouldn't have started to work when you unplugged it and plugged it back in

Put a stick on the brake pedal so brake lights are on, check 3rd light to be sure its on
Turn on Park lights
Then use a volt meter or test light to check the Brown wire on the frame side connector, Parks lights
Meter or test light should be grounded to frame or clean metal
Park lights are to test if meter or test light is working

Then test Light Green wire, brake light wire from switch in cab
If no 12v then you can check the wire in the frame or just run a new wire to the brake pedal switch, trying to find a broken wire can be a real waste of time, vs accepting that its broken, have a quick look near it and then just run a new wire

If light green wire has 12v, then my guess is that the problem is in the connector, bad pin or slot

And listen to Uncle Gump, that light green wire goes to drivers side brake light and splits to passenger side, so could be and issue in the harness that goes up to drivers side tail light lens, easy to take lens off and have a look

 

[Boostaddict91]

That's exactly what I did, I just spliced into the switch at pedal and ran a new wire to the taillight now they work like they should. See if this lasts more than one trip haha

 

[RonD]

Good work