Brake Light Help

Kaonix

Kaonix

Member
Hi guys,

You guys have all been great helping a noob with getting into the old ford hobby and getting my 41 Coupe to where we want it to be. So, Thank You!

To my problem:
As mentioned I have a 41 Ford Deluxe with the original Flathead V8. I'm having trouble with my brake lights. Well, I don't have any lol. Can someone point me in the right direction as far as diagnostics? I don't know exactly where the brake light switch is and how to properly diagnose whether the switch is bad or I need to look further down the wire.

The car has been converted to 12 volts and the tail lights work just fine. Hit the brake pedal and nothing happens. The tail lights stay on, just no brake lights.

Any help would be greatly appreciated. If you need anymore info to assist me in diagnosing this problem please just ask and I will do my best to provide. Do please understand that although I'm not a novice mechanic by any means, I am somewhat new to these older systems.

Thank you!
 
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The brake light switch is on the back side of the master cylinder (under the floor on the drivers’ side), you'll see two wires connected to it, one hot and one going to the brake lights. You can use a "jumper wire" to bypass the switch and see if the lights come on. If the brake lights come on, the switch is bad. You can get switch at most auto parts places; I think Ford used the same switch from '39 up to the mid to late '60's.
 
Ok, I've done that, and still no brake lights. Any ideas? Also, Thank You for your quick response. I've actually been following your Zephyr trilogy and must say, I'm ENVIOUS, LOVE your garage!
 
Check the bullet connectors on the brake light wires and check to make sure you have a double filament bulb.
 
Thanks, I've waited a long, long time to have a garage that I was actually able to work in. Like Gary says, check all your connections, you might have a broken wire in the harness coming down to the master cylinder and/or in the harness going to the taillights.
 
Ok, I'll check all those things. Also on a different note, I was wondering if anyone knows anyone locally in my area that might have a spring spreader or access to one? I don't have the resources now to make one nor do I have the cash to purchase one at the moment with xmas and all coming up, things have gotten a bit tight.
 
THE FIRST thing to do is check both connections at the switch on the master cylinder with a volt meter or test light to see if one side it hot. It doesn't matter which side is hot. Then you know which way to look. If there is no power, you must trace the wire back to the power source to see where it is open. If there IS power to the switch, you must determine if it closes (has power to both sides) when the pedal is pushed. If you have power that far, then you must check the load side (to the lights).
 
I did check the switch and I do have power to one side. I then jumped the power to the other side and no result. No brake lights.
 
Kaonix said:
What should I see when I hook my multi-meter up to the light socket?
Click to expand...
you should have 6 volts, make Shure that you have your meter on DC voltage
also check for contuity from the outer shell of the socket to the fender. maybe you have a bad ground
 
Do you have signal lights.Stop circuits goes thur signal light switch.
Ohm out stop light pin rear to under dash.
 
Brendan said:
you should have 6 volts, make Shure that you have your meter on DC voltage
also check for contuity from the outer shell of the socket to the fender. maybe you have a bad ground
Click to expand...

With the system being converted to 12vdc will I still see six or will I see twelve?

Do you have signal lights.Stop circuits goes thur signal light switch.
Ohm out stop light pin rear to under dash.
Click to expand...

I do have signal lights however I've removed everything related to the signals trying to eliminate as many complications as possible.
 
This is way to under stand whats going on.
Speedway has signal light switch 91062860
You will see that the stop light wires goes thru sw.
Thats the problem.
Or put all wires back were they were and get a 12 volt flasher.
 
Re: Post #14. With a converted system, you should see 12VDC. No need for a resistor in the stoplight circuit since we're just lighting bulbs. The only way to be sure what you have is to check voltage at every connection in the system. Could be a broken wire or ???? Get your VOM and a buddy to press on the brake pedal for you. Good luck.
 
I had this very same problem with my wifes car, power on one side not the other, esisit way for me was just to climb under the car with a test lamp find the hot powered side then put the probe on the other conector, pull the break pedal down and you should get power through to the other side, in my case I would only get power through if you really stood hard on the brakes, say for an emergency stop, grabed a new switch and BAM problem solved
 
Ok. Thanks for all the great input guys. I'm gonna have someone help me tomorrow with the pedal pushing. I did notice one anomaly: when I have my running lights on i.e. just tail lights, I get 12 volts on one contact in the light socket, and around 9 on the other. Is that normal operation?
 
What state do you live in? Maybe a Barn member could help you. Your problem should not be hard to find.
 
Oh, guess I should update my profile, didn't realize my location was blank. I live in the Phoenix AZ area.
 
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