No rear turn or brake lights.

[Mightyfordranger]

New truck don't have rear brake lights or turn signals....dangit!

07 150

Truck is wired for trailer brakes etc

Where would you start? Has new bulbs too

 

[Curious Hound]

Check the connections for the trailer wiring harness. May be a bad installation there. Also check the ground connection for the rear lights. That is often on the rear cross-member.

 

[ElectraRider]

check your fuses, I found that issue on one of our work trucks.

 

[Mightyfordranger]

I think it's a loose wire I noticed they would work then hit a bump and they would quit

 

[RonD]

If the F-150 is the same as Rangers then there are TWO separate wires, one for stop/turn on left and one for stop turn on the right

The multi-function switch(turn signal stalk) is where stop and turn is combined in Rangers

Does the dash and front turn signal bulbs come on but don't flash, or do they flash?

And as far as you know are the rear bulbs stock, or LED?

 

[Mightyfordranger]

If the F-150 is the same as Rangers then there are TWO separate wires, one for stop/turn on left and one for stop turn on the right

The multi-function switch(turn signal stalk) is where stop and turn is combined in Rangers

Does the dash and front turn signal bulbs come on but don't flash, or do they flash?

And as far as you know are the rear bulbs stock, or LED?

The front light come on and flash the dash lights too.

But the dash lights flash rapidly like as if the bulbs are burnt out. And they are regular filament style bulbs. The running lights work in the back so when the headlights are on they come on too. But it's intermittent function on one side or the other for brake lights and turns.

It will switch from neither side having working turns or brake lights. So if you tag a pot hole and poof now ya got driverside turns and brake. Tag another pot hole poof..gone. but the front turn signals work properly and consistently. It's just the rears.

 

[RonD]

If park lights work in the back the ground is most likely OK
You can try Reverse light just to confirm good ground

So you are down to the connector for those 2 wires, which is at the rear, should have 4 wires
Park(license plate)
Reverse lights
Left turn/stop
Right turn/stop

Maybe a 5th for ground

And this is where people ADD trailer lights, so wires can get a bit butchered

Only other place would be at the multi-function switch
The front and dash turn bulbs share a wire, for each side
Then separate wires combining stop and turn go out to the back

The 4-ways(hazards) share those 2 rear wires but key can be off when using them
Which is handy when testing, see if they work or if wiggling wires gets them to work

So there is no separate brake light wire except for the 3rd brake light on the cab, does it always work?
This wire is direct from brake switch on brake pedal

 

[Mightyfordranger]

Ok so had the truck at my buddies shop. We figured out that the harness coming down the frame is fine works properly. But as soon as it's plugged into the other half like the actual trailer plugs and lights etc it's stops working. What even weirder is that you can light each light individually just fine. If you supply ground or power where needed. But plug em together...nope shite.
I wonder if ya can buy that whole harness half offline someplace.

Also the harness seems fine too it's not chewed on or muffed up

 

[97RangerXLT]

check the connectors really well where it plugs into the other half. my guess is a pin is getting pushed back and not making good contact.

AJ

 

[Uncle Gump]

check the connectors really well where it plugs into the other half. my guess is a pin is getting pushed back and not making good contact.

AJ

Seems like a solid recommendation to me.

 

[Mightyfordranger]

Iirc there wasn't any that were loose, it all seemed fine?

 

[RonD]

Iirc there wasn't any that were loose, it all seemed fine?

Well that's not true or it would work, lol

How many wires are there on the truck side?
Ground?
Reverse light
Tail light/license plate
Right turn/stop
Left turn/stop

Trailer brake?
AUX 12volt?

You can get a trailer wire plug SET, both male and female ends, and use that to replace the Ford connector

 

[Mightyfordranger]

Well that's not true or it would work, lol

How many wires are there on the truck side?
Ground?
Reverse light
Tail light/license plate
Right turn/stop
Left turn/stop

Trailer brake?
AUX 12volt?

You can get a trailer wire plug SET, both male and female ends, and use that to replace the Ford connector

I'm not near the truck currently it's at a friend's shop yard. And trying to remember is proving difficult. But that's not the worst idea swapping out the plugs for something better. I been meaning to buy a weather pac connector set.

Though I might see if I can pick up another harness from a junkyard near by and see if that works. Couldn't hurt.