No brake lights

winnipaw · #1 (**permalink**) 09-22-2012, 06:13 PM

While trying to trace circuit continuity, to find brake light outage, I traced the lead up through the steering column to the four way flasher. Would this circuit continue to the brake circuit, or would the brake wire be separate? I dont want to run a whole new wire from the brake switch to the rear brakes. Any ideas?

Tommy · #2 (**permalink**) 09-22-2012, 06:40 PM

Wiring can vary from car to car, so without knowing more about your particular car, your question is difficult for me to answer. .... But, the most common cause for brake light failure in a fiberglass body car is a bad ground. Before I started tracing wiring though the entire car, I'd either check the ground connection to the brake lights, or run a homemade jumper wire from the brake light ground terminal to a known good ground. If the lights start working, you've found your problem.

winnipaw · #3 (**permalink**) 09-22-2012, 07:23 PM

My car is very much a Ford mustang with a Ford Steering column and fuse panel. All grounds have been checked and are good. The mystery is why the brake wire fom the switch goes up through the steering column loom. Where does it end in the steering wheel hub? I cant find any continuity in the steering column.

Barnsnake · #4 (**permalink**) 09-22-2012, 09:27 PM

On many vehicles the brake lights are inter-connected with the turn signals and the emergency flashers. Many use the same bulb filament for brake lights and signals. If they weren't inter-connected the rear signals wouldn't flash while the brakes are on. It makes for a potentially confusing circuit.

winnipaw · #5 (**permalink**) 09-23-2012, 07:41 PM

Thanks Jim. I guess I'll continue to play with my test light to find that circuit within a circuit. If anyone has a solution,let me know.

Tommy · #6 (**permalink**) 09-24-2012, 03:55 AM

winnipaw,
I just did a Google Image search for the words "four way flasher schematic." It returned more than 20,000 images. Perhaps looking at a few of them would help you understand how your car is wired. Or maybe you can get lucky and find the schematic for your particular car.

WPa Cobra · #7 (**permalink**) 09-25-2012, 11:15 AM

My lights quit some time ago...2nd thing I checked was the brake switch....bad switch....bought 2, they are cheap !

YerDugliness · #8 (**permalink**) 09-25-2012, 11:30 AM

Quote:

Originally Posted by WPa Cobra

My lights quit some time ago...2nd thing I checked was the brake switch....bad switch....bought 2, they are cheap !

I will soon change the way my brake lights are actuated. Right now they are actuated by a "plunger" switch that makes connection between the two terminals when I push on the brake pedal. That has proven to be unsatisfactory, as there are times when the contact pad becomes dislodged from its location and then when the brake pedal is released the lights continue to shine brightly.

Soon I am going to replace the brake master cylinder and will use a pressure activated switch operated by an unused port on the master cylinder.....I think that will be a more reliable manner of switching the brake lights, as I currently have to climib under the dash at least once a week to reposition the contact pad

!

As for the wiring routing....my car uses what I think is a Pinto steering column, might be a Mustang II column, I don't know. All it has is a turn signal lever on the left side of the column....but I think the wiring goes up into the column from the plunger style switch down under the dash.

Cheers!

Dugly

PANAVIA · #9 (**permalink**) 09-26-2012, 10:44 PM

If they used a mustang column then the same year mustang manual or diagram, might give you vision into the color codes and or wiring , at least a starting place -

winnipaw · #10 (**permalink**) 09-28-2012, 05:52 PM

I know what you mean about that funky brake light switch. I tightened the whole assembly and lubed the pivot pin. It seemed to help alot. Unlike you, I am OK with the brakes on my car. There is always room for improvement on brakes but so far so good. I'm waiting for your results. You have a much better system than I have. Still looking for my rear lights to come alive.

Dwight · #11 (**permalink**) 09-28-2012, 06:17 PM

we have four or five Cobras in our group with the pressure switch for the rear brake lights. They do not come on till the switch reads 35 PSI. A lot of times they can apply the brakes and the lights do not come on.
A couple of them are going to go with the pedal switch.

I have 36,000 miles on mine and it works!

Dwight

YerDugliness · #12 (**permalink**) 09-29-2012, 09:48 AM

Quote:

Originally Posted by Dwight

we have four or five Cobras in our group with the pressure switch for the rear brake lights. They do not come on till the switch reads 35 PSI. A lot of times they can apply the brakes and the lights do not come on.
A couple of them are going to go with the pedal switch.

I have 36,000 miles on mine and it works!

Dwight

Surprisingly, I may have solved the problem.

I crawled under the dash yesterday to glue some sort of a "shim" under the part that frequently falls out of position...it is loose enough that if I push it up into position with my finger, as soon as I take my finger away it just falls back down into a position that will not make contact with the plunger. I needed a shim of about 3/8" thickness...crawled out from under the dash and headed for the cabinet in the garage to look for a plastic carpentry shim to cut to size when I realized I was walking on a perfect material for the job, some of that foam pad type garage flooring that just clips together. I had a hunk in the cabinet, so I took a razor blade to it and cut it to shape. Once I had lodged it (no glue needed) between the offending contact pad and the brake pedal lever, the pad stayed in place. I took it out for a test drive, cannot duplicate the problem now. I think the issue is resolved

....as they say, necessity is the mother of invention

Quote:

Originally Posted by winnipaw

I know what you mean about that funky brake light switch. I tightened the whole assembly and lubed the pivot pin. It seemed to help alot. Unlike you, I am OK with the brakes on my car. There is always room for improvement on brakes but so far so good. I'm waiting for your results. You have a much better system than I have. Still looking for my rear lights to come alive.

Winnipaw, I'll keep you posted on the progress on the brakes. I spoke with the Wilwood rep the other day, got the part numbers for the O-rings for the pistons to rebuild the 4-piston calipers, and I have sourced a decent 1" diameter piston 'Vette style master cylinder. I'll probably perform the upgrade over a weekend sometime in November....October seems to be QUITE full on the weekends for now.

Cheers!

Dugly