I have a '76 F250 and the brake lights just went away. I replaced
the switch at the pedal,replaced the fuse and still no lights. I have
running lights so that should rule out the ground. I also have power at the switch connection. Any body have any ideas.
Thank's

 

Do the turn signals and flashers work?

 

Start with the obvious: Bulbs & sockets. It's not uncommon for one of the elements in the bulb to burn out. Once one goes, more power is going to the other and can burn it out too.

Use a volt meter and test the power to the brake terminal in the socket. Also, clean the socket good. They tend to corrode a bit.

Good luck.

Kevin K.

 

Yes the flashers and turn signals work.I checked out the bulbs and they were ok,replaced them anyway still no luck.

 

You said there's power TO the swich, right? What about FROM the switch?

First, I'd bybass the switch by by running a wire from a hot source to the wire that goes back to the lights (after the switch) because new parts don't always work. Or, take the wires out of the switch and touch them together.

If you still have nothing, jump a long wire from the outbound side of the switch back to the lights and hit the brakes. This will bypass the existing wire that runs back there.

I'd also follow the wire from the switch all the way back and check for broken or worn spots.

Also, check the fuse again in case a short blew it right away.

Good luck.

Kevin K.

 

First, make sure it is not the bulb.... After that check the connector that the wires plug into from the tail light housing. And then check the wires for cracks or wear.... The easy'st way to replace the wiring (if that is your problem) is to go buy a wiring harness for a long trailer and it comes with all of the wires and connectors you need.... Good luck! Wiring is a pain...

 

Correction, Sorry guy's I have running lights and turn signals,no
flashers at the rear.I jumped a wire from the switch to the 4 wire
connecter at the rear. Was able to identify left and right turn and
running lights,but when I jump what should be the brake lights,
the only one left the back up lights come on.I know this stuff is
hard to diagnose without being there but any additional ideas
would be appreciated,and thanks for the help so far.

 

Did you check the bulb? You say you dont have any power to the brake light wire that goes to the rear? Get out your tester and test the wires in the tail lights doing everything, blinkers, flashers, and brakes. Post the results. Also have you checked out the wire condition ? Sounds like you could have one grounding out somwhere.... That can cause a fuse to blow or a bulb to burn out...

 

OK lets stop and think for a logically for a second
The brake lights use the same wires and light bulb filaments as the turn signals, from the turn signal switch to the rear of the truck.
So if the turn signals work it isnt wiring or bulbs.
The turn signals and running lights use the same ground as the brakes.
So if they work the ground is good.
If power is going into and then out of the brake switch when the pedal is pressed then the fuse and switch are both good.
The brake light power feeds into the turn signal switch and then out to the brake lights....as long as the turn signal switch is centered, turn signals off.
So if you never have brake lights with turn signals off, selected to right and selected to left.....then the problem could be the wire from the brake light switch to the turn signal switch, red black striped wire, or the turn signal switch itself.
Another thought the hazard flasher and turn signal flasher have been known to screw up the brake lights thru the wonders of electricity if they are defective
Hope this helps.

ps
This only works on stock wiring any modified wiring may confuse the issue even more

 

My turn signals are below my brake lights.... maybe somone re-wired them ? Because I have one bulb on top of the light and it is a single filiment and the one below it is a double... is that normal?

 

I have checked out everything.I did notice while messing with
the flashers,which by the way worked fine before,that I have to
set the flasher switch at the halfway point to get the front flashers to work.I ordered a new turn signal switch.I'll let you
know what happens. Gotta be it,I hope.
Thank's

 

Are you talking about the backup lights?

 

Normal no...the way Ford should have made the lights yes
Stock rear lights have a double filament bulb on the top, turn/brake and running lights, and a single on the bottom, reverse lights.
When you have the brakes on with say the RH turn signal on.....you will see a LH brake light and a RH turn signal.
I change my trucks over to separate brake lights as I like the two brake lights and separate turn signals...also I do not particularily enjoy working on the turn signal switch

 

I have the same problem with a 79 F350. Liking simple under the hood, I unplugged the cruise control unit and threw it in the trash. Does anyone know if the brake lights need to have the cruise connected to work or is it coincidence?

 

The cruise control gets its power from the horn circuit.
The cruise brain box plugs into a always powered circuit.
The wiring in the steering column is what takes care of turning the horn circuit to a cruise & horn circuit.

When a truck gets cruise control is gets a special brake circuit harness.
With cruise : the brakes lights are actuated by the brake switch which is attached to the pushrod to the master cylinder.
The switch on the side of the pedal is the cruise shutoff switch.


Without Cruise: the brake light switch is a 3 1/2" plastic slip switch that attaches to the side of the brake pedal.



So if you never want cruise control again you can remove all the wiring from behind the dash.

I can answer any specific questions you may have!