I have no brake lights and need some help. I have tail lights, hazards, left and right turn, but I don't have brake lights.

The previous owner said there were no brake lights and he had replaced the brake switch under the hood. There is a red wire on it closest to the firewall which goes into the cab. It has power when Accessory on. From that wire that goes in there is another red that routes down to the frame rail. It has a quick connector. I disconnected it and I get know power from the end that comes from in the cab.

On the other side of the switch is a green wire that goes down to the frame rail. When on Accessory and a jumper between those two poles on the switch the solenoid triggers, but no lights.

What does the green wire go to?
What does the dead red wire come from?
Any ideas on where the problem is?

Thank you for your help.

1966 F250 2wd V8 Auto Camper Special Custom Cab

 

Do you have a flare or styleside bed?


Make sure you have 1157 lamps and the sockets are clean with good contacts.


3 wires go to the rear. Brown, green, yellow.


The brown is tail lights, yellow left turn, green right turn.


On the left side, in front of the rear wheels is the connector for all 3 wires. Take your test light and check the function of tail, brake, and turn signals there. That will tell you if the problem is in front of or behind that connector.

 

Thanks
It's a styleside.
I do have tails, left, right, hazard, and hazard with tails. I get power to brown, yellow and green for all of those lights.
I'm not getting a brake signal back. I don't know where the wires route to off of the brake switch.

 

C1AZ-13480-A (replaced 0A-13480) .. Brake Lamp Switch (Motorcraft SW-24) / Available from Ford & auto parts stores.

Applications: Myriad 1940/66 FoMoCo vehicles.

This switch is pressure activated by stepping on the brake pedal. It's notorious for getting gummed up with dirty brake fluid.

So, even though the switch was replaced not that long ago, if the brake fluid is dirty, it has gummed up.

 

Thank you
How do you test that the switch is gummed up versus an electrical failure into the cab? Could it be the turn signal switch?
I don't know where and what the wires on it go to. That green seems to drop into a wire loom but not sure what it connects to. The red that goes into the cab I'm guessing goes to the turn signal switch but the other red seems to go into the loom and not sure where it goes either.

 

I'd replace the switch, see what happens. It's probably no more than 10 bucks if bought from auto parts stores.

This same switch* was also used on myriad 1947/66 Studebakers & 1948/58 Packard's (except 1955/56's with Torsion Bar suspension).

*The Studebaker/Packard part number was: 666858

 

Short the two wires together that attach to the brake light switch and it will act like the switch is On full time. Then you can check voltages without regard to whether the switch is good or bad since it won't be in the circuit at that point. I use a bolt that fits into one end of the plug and then cut the head off and insert into the other plug. Makes a quick way to short them together without removing the plugs from the wires.


.

 

But when I jumper the wire on the switch or press the brake peddle I get the solenoid to trigger. So I have power to one side of the switch and then it fires when triggered. What wire actually runs to the back for brakes? Is that the green wire? I wonder if that other red wire is for flashers.
I will have to stop by my parts guy tomorrow to get a switch. He closes before I can get there after work.

 

The top photo is the standard factory 66 f100 wiring , lower photo is the added optional accessories . Hope this help to trace and sort out the issue .

 

If you use a multi meter you can set it on ohm and trace out the wires
I believe that the red goes through the turn switch

 

Guys, I may be stepping outside of what I know, but it is a switch........one side, in this case, is hot (+12Vdc and has been verified by AubryA3 as hot and the wiring diagram shows it coming from the ignition switch) and the other side would be the "delivery" wire to the element in the bulb......when the switch is closed, power is delivered to the element (ground is at the bulb) completing the circuit......why would it go any where else (electrically)? If the wiring harness isn't modified, then it would go to the bulb element, although it may route to places as shown in the wiring diagram.

What Schoo is saying to ohm out the "delivery" wire to the element (and other wires) would see if there is a direct connection to the bulb element and this should be checked, however, what "ohming" doesn't confirm is if the wire goes somewhere else (I don't get the solenoid issue)....if the wiring harness is modified, good luck to know exactly where a connection goes.

If the switch is good and it does not matter on the the "delivery" wire to the bulb element, disconnect that wire (properly cap off and abandon it). Supply a new wire to the rear brake light, if power is at the switch and the switch is good, wouldn't this would solve the problem? m

 

Now I am completely confused

 

the common element is the turn signal switch , power goes to the brake switch from there it goes to the turn signal switch where in the center position it allows the brake lights to function normally , when the lever is moved to activate the turn signals the circuit to that side is moved and rerouted in the switch to allow the flasher to function blinking that side and the opposite side to remain a brake light . first place I would draw my attention to is the turn signal switch and wiring at the column and back to the flasher to the brake switch and back to the fuse box .

 

TxStang2010.......aren't the bulbs dual element? One for the turns and the other for the brake? m

 

Looking at the first diagram above I need to have the green wire from my brake switch go back into the cab and to the turn signal flasher. I get power to the other side of the brake switch so that tells me the connector from it to the turn signal switch is good. It's the flasher that is not getting power for brakes. But there is a solenoid (the flasher?) that triggers when I jump that wire. I'll have to find my flasher and see if I have the right wires.