Brake lights

[xero0620]

What would cause my brake lights to momentarily work and then stop? Or sometimes work and sometimes not? I wiggled the wires and the bulbs and nothing.

 

[zookeeper]

Check the swicth. If it's not making good contact with the mastercylinder rod, they'll do goofy things to the brake lights.

 

[xero0620]

Where is that switch located and if its not making contact how do I fix it? Sorry but I new so hang with me.

 

[xero0620]

Ok the tail lights work and turn signals work. When the brake pedal is pushed we get no indication in the lights. So I dont know where the mastercylinder and the switch make contact. If its under the steering column, there are so many wires and crap up under there that I cant see much of anything. Ill look if you can point me in the right direction. Thanks.

 

[zookeeper]

Follow the brake pedal up under the dash, and just above the column, you'll see where it pushes on the master cylinder rod, going towards the firewall. Here's a link on the adjustment basics, hope this helps.
http://forums.stangnet.com/757121-brake-light-switch.html

 

[xero0620]

Thanks for that link, it will help. I found the switch last night and I cant tell how old it is so I just ordered a new one. Do you think I will need to adjust the new one?
Also to get the old switch off do you just remove the pin through the bar and pull the bar from the pedal and just line it all back up on the install?

 

[zookeeper]

I had to adjust my new one to get it to work. In retrospect, I probably could have adjusted my original to get it to work, but I didn't know that. My brakelights all worked when I was doing the mock-up, but I put in a new master cylinder after I painted the car, and the new m/c pushrod was just different enough to not allow the switch to be pushed in. I had to ask my Dad, who'd been working on cars since the second one rolled off the assembly line, and he pointed me in the right direction.

 

[zookeeper]

Also to get the old switch off do you just remove the pin through the bar and pull the bar from the pedal and just line it all back up on the install?

Yes, the switch removal is pretty straightforward, but it's a bear to see how it all goes together
under the dash. I've had mine apart so many times to tweak it, I can do it by feel alone. I don't know if that's bragging or complaining...

 

[xero0620]

ok i got the switch out and messed with it. Bent the two ends that your supposed to bend but still no brake lights. I got the new switch coming tomorrow and I hope that fixes it.

Main problem is I cant get it all to go back on the pedal so I can put the pin back in. Is there a trick to it? There are some plastic spacers and such that go on there but with everything put back on the way it came off, I cant get the end of it to stick out enough to put the pin back in. Any help would be great.

 

[zookeeper]

You mayhave to wiggle the pedal at the same time you push the pushrod/switch onto the stud on the pedal. Typically the hole on the switch is a VERY snug fit on the stud, which makes it tough, but a little patience and wiggling will get it on there.

 

[zookeeper]

Another thing to check is to make sure you have power to the switch. No matter if the brakes are on or off, one of the wires will be "hot", the switch just completes the circuit, sending power to the lights. Use a test light to make sure there is power available at the switch. There are only two wires, one of them needs to have power. If not, I think the turn signal switch in the steering column is the next switch upstream, and also a cause of brake light problems.

 

[xero0620]

I also read a thing that said you can push the contact down yourself and see if the switch works at all. As far as testing the wires, I could use a multimeter to do that, like checking for cont. correct?

I hope its not the turn signal switch as I just replaced the cam in there, but when I have the brakes pushed in and the turn signals on there still isnt any indication that the brake lights want to work.

I dont know if I said this earlier but when I pushed the brake peddal in the day I was told they were not working, I had my wife stand at the back and look. They were working at that time and this is not 3 minutes after I was told they were broke. So we swapped spots and she put the brakes on and I looked and as soon as I went back there I saw the lights go out and they havent worked as brake lights since. But turn signals and tail lights work.

 

[zookeeper]

I may be wrong, but if your turn signals work, then you know the bulbs and wiring are good, since the turn signals are the same lights as the brakes. That also seems to indicate that your signal switch would be good since it obviously has power, since the signals themselves work. That only leaves the brake switch, in my opinion. Test the switch if you can, closed should show no resistance if testing with your multi-meter. I tried testing mine, but couldn't juggle my multi-meter leads while depressing the plunger on the switch, so I just popped for a new switch and hoped that was it. If your switch tests good, and you have power at the switch, then I'd say it's just a matter of tweaking the tabs until the brake lights work.

 

[NewStangOwnr]

I have a weird problem maybe someone could shed some light on. (haha no pun intended)
One of my brake lights is really bright, and one is dim. Tailights work. I am honestly stumped.

 

[xero0620]

Ok zookeeper, I got the new switch on everything put back together and still came up with nothing. So I took the switch off to adjust the tabs and I can see where the mastercylinder arm made contact with the switch. So I went and bought a test light. Tested the plug and one side is hot and made the light come on. This means what?

How do I test the actual switch? Do I clip it on the hot part of the switch and then touch the hot part of the plug, then press the brake pedal? If so I did that and the light does not come on.

I just dont see how if there is power at the plug and when I press the brakes and the switch makes contact why it wont work.

 

[xero0620]

Well, Im close to giving up. The switch is getting power but for some reason even the new switch is not sending power. Even when I hold the test light on the part that is pushed by the master cylinder and push it down with my finger, it still wont light up the brake lights.

 

[zookeeper]

Did you try bending the tabs? The plunger needs to move quite a ways to close the circuit.

 

[xero0620]

bent the tabs still didnt work. Your really going to love this one though. I took a spare wire I had laying around and stuck one end into the power in on the socket and then put the other end into the out side. Taking the switch out of the equation and forcing the circuit to be continued. So after I did this I got the test light and tested both sides and they light up. So power is there. But.......

Still no brake lights. In this configuration they should be on all the time as if the pedal was being pushed correct? I have no idea where the wire goes from the plug. There was an aftermarket radio installed and an alarm system, there are so many wires under there I cant see anything. If its not the switch, plug, or the power wire then what the hell is it?

 

[zookeeper]

Well, now it's time to do some searching. First, you need to make sure the switch is working correctly as installed. It should have power to one side all the time, and no power when the brake is not depressed. Then bend the tabs until it has power to both sides only when depressed. Once you have confirmed that the switch is working correctly with either a mulit-meter or test light, then follow the wire rearward until you find the break. Some where along the line between the brake switch and the taillights, you have an open circuit, either a broken wire or two bare spots touching each other. My fastback had a ball of electrical tape in the trunk covering the wires where the entire loom had been cut, evidently from someone tossing something in the trunk. The loom (at least on my car) goes from the switch, under the dash, down the driver's side under the sill plate and into the trunk. It's a very short and very simple loom and don't forget to make SURE you have a good ground as well.

 

[rbohm]

was the master cylinder replaced recently? if so make sure the plastic bushing that is installed in the push rod opening where it connects to the brake pedal has been removed, otherwise the brake switch wont be pushed far enough to light the lights.