My break lights are out on my 1966 F100. The fuses are all working. When I turn on my headlights, the running lights do come on the rear. Turn signals on the rear don't work either, but it is the same tail light.

Where do I look next?

 

Brake light switch located at master cylinder. It's the pressure type activated by brake fluid when you step on the pedal.

The switch is notorious for getting gummed up with dirty brake fluid, no longer works. Same switch 1940/66, EZ to find in parts stores.

Bulb sockets corrode, use a pencil eraser to clean them.

 

almost sounds like the turn switch is bad as the break lights go through the switch then to the rear

 

Do your turn signals work in front? If totally inoperative, then I would agree with Jack that you need a new T/S switch as both brakes and turn signals route through it. Also agree with ND that brake light switch might be an issue, but as you have two problems and both route through the T/S switch, I would look there. If you do order a new T/S switch, make sure you pay more and get a real Ford one and not some foreign POS.

 

Guys please be careful, don't break anything while you are repairing the brake lights. OK??




John

 

My turn signals do work in the front, yet they have always had a weak flash. Sounds like I just need to order both switches and see what happens.

 

Pull the two wires off the master cylinder and connect them together. If the rear lights work, then the sending unit on the m/c is bad.

On the fronts, open the hood and look down at the back of the turn signals. You should see 2 sheet metal screw and a 3rd machine screw with a nut on it on the back of the turn signal housing.

The machine screw is the ground, check to make sure each turn signal is properly grounded. The nuts were missing on mine, I replaced them and they work perfectly.

After 45+ years, things tend to corrode. I unplugged all my light connectors, cleaned them as well as I could, and put a dab of diaelectric greese on them, they work much better now.

 

Check this out.

Ford Truck Turn Signal Switch C9TZ 13341 C 1965 1966 1967 1968 1969 | eBay

 

Really? I learn something new every day.

 

ebay seller (I wonder who this is? ) says it's obsolete, hard to find. Seller is correct that FoMoCo just obsoleted it, but it's not that hard to find...when one knows where to look, that is.

GREEN SALES CO. in Cincinnati OH has 5 = 800-543-4959.

CARPENTER NOS OBSOLETE PARTS has 881 = 800-476-9653.

Now you know why it's obsolete .. cuz Carpenter bought all of FoMoCo remaining inventory.

 

I connected the wires off the master cylinder and my break lights came on!!! So I'm going to change the Sending Unit and hope that fixes everything.

Where is the best place to pick this part up? is there a proper name or part number i should look for?

 

C1AZ-13480-A (replaced OA-13480) .. Brake (Stop) Lamp Switch.

ALL 1940/66 FoMoCo vehicles, available from a gazillion autoparts stores.

 

Found it under the name of a Stoplight Switch at Advanced Auto Parts

 

Hello all, found this site today and thought I'd join after reading the helpful info everyone seems to be happy to pass along...i have a '66 250 CS lwb with half of the rare Ranger package---Bucket seats, no console though (never was one in truck) with 74,XXX original Texas miles on it. Mostly all original paint with nice patina hood (along with the notorious kink in the center). All stock, Cruise-o-matic was freshened up shortly before I bought it. Buying from a true mechanic has a lot of pluses!
I read some discussion of various turn signal/light issues and found some info helpful. My issue is turn signals work really fast, blow fuses. Brake , parking and headlights always function normal. Last summer I installed a new signal switch, as I tought that to be issue of being worn. That did not correct. I have also swapped out flasher as well. The truck does have trailer brakes which i know nothing about, whether that may have something to do with it. Just wondering if any of you folks have fresh ideas?
It's nice to have a site like this to kick around ideas. Thanks, Jeff

 

Jeff: I'm guessing your truck has an emergency warning flasher option in it. If so, your truck will have TWO flashers in it, one for the emergency warning flasher and one for the turn signals. Also, fast flashing turn signals are a sign of having a very heavy duty flasher installed, which you would do if your turn signals were supporting not only your truck but a towed trailer as well. It would have to support an additional set of turn signals (belonging to the trailer). My guess is that you replaced the flasher for the emergency warning lights and not the one for the turn signals. That would explain the fast flashing to me. The blowing fuses are likely caused by a different issue - usually a short. Look for loose or bare wires or bad grounds. And yes, your trailer brake controller might be (but shouldn't be if properly installed) a factor, depending on what kind of wiring job the installer did. Hope this helps you!