brake light out on dash stays on

[RU2CHKN]

I know what the light on the dash means, it means one of my brake lights are out. But when I had someone step on the brakes, all the brake lights work fine. I checked the bulbs and they were good. Does anyone know how to fix this problem?

[Chris Crash]

Maybe it's the lamp failure box?

[LynchburgCSI]

When was the last time the bulbs were changed? When a bulb gets ready to burn out, the resistance goes up. This generates heat and causes the filament to burn out. The tail light out box only looks for changes in resistance. It DOES NOT look for breaks in the circuit (ie- a burned out bulb). So, in a way, it can actually predict when a bulb is getting ready to go out. About 90% of the time that's usually the issue I see when people post up this problem. Just wait and see what happens or get a jump on it and replace all your bulbs.

[RU2CHKN]

^Alrighty I'll look into that

[73sport]

Originally Posted by LynchburgCSI

When was the last time the bulbs were changed? When a bulb gets ready to burn out, the resistance goes up. This generates heat and causes the filament to burn out. The tail light out box only looks for changes in resistance. It DOES NOT look for breaks in the circuit (ie- a burned out bulb). So, in a way, it can actually predict when a bulb is getting ready to go out. About 90% of the time that's usually the issue I see when people post up this problem. Just wait and see what happens or get a jump on it and replace all your bulbs.

I'm gonna have to bust your chops on this one. . . .
A cold bulb has very low resistance. As it heats, the resistance goes up. When its cold, the current is highest and thats when bulbs typically go super-nova turning into a flash bulbs. Anyway, high resistance = less heat which = less power.

As far a bulb life goes, that's a different story. What happens is the thin weak spot is trying to pass an equal amount of current through the entire filament including those thin spots where the tungsten was not re-deposited. The thin spot can't handle all that current so the thin junction overheats and the bulb opens, but as you stated, the system looks for this.

P = V * I => which is Power in watts where (V = voltage) and (I = current in Amps)
13v/1000ohms = 0.013amps or => 13v*0.013A = 0.169watts
13v/10ohms = 1.3amps or => 13v * 1.3A = 16.9watts

[ajkalian]

Originally Posted by 73sport

P = V * I => which is Power in watts where (V = voltage) and (I = current in Amps)
13v/1000ohms = 0.013amps or => 13v*0.013A = 0.169watts
13v/10ohms = 1.3amps or => 13v * 1.3A = 16.9watts

I don't now much about this E=I/R stuff, but I had the same problem, and took out the Lamp Failure Box, took it apart and looked inside. Then put it back, cause I didn't have a clue as to what was going on in there.

Then I took a look at the loom of wires on the driver side that goes up inside the trunk lid. I wiggled some of them, because other TN members say that the wires sometimes fray over time.

So after all that Ram-a-Lam and me doing nothing but wiggle some wires, and look at stuff, the light on the dash went off, and it has stayed off.

So I'm guessing in my case I have a loose wire someplace, and as long as the light in the dash is off, I don't care where it is. But sooner or later I got a feeling that I'm gonna have to rip all that wire out of all of the looms, and take the cover off the trunk and get my multi-meter out and trace out all the wires to find the one that's causing the problem.

So it might just be a mechanical problem, not an electrical one.

[Bankos66]

When my brake light came up it was because one of the sensors got jammed and it kept the light on....maybe that could be it

[LynchburgCSI]

Originally Posted by 73sport

I'm gonna have to bust your chops on this one. . . .
A cold bulb has very low resistance. As it heats, the resistance goes up. When its cold, the current is highest and thats when bulbs typically go super-nova turning into a flash bulbs. Anyway, high resistance = less heat which = less power.

As far a bulb life goes, that's a different story. What happens is the thin weak spot is trying to pass an equal amount of current through the entire filament including those thin spots where the tungsten was not re-deposited. The thin spot can't handle all that current so the thin junction overheats and the bulb opens, but as you stated, the system looks for this.

P = V * I => which is Power in watts where (V = voltage) and (I = current in Amps)
13v/1000ohms = 0.013amps or => 13v*0.013A = 0.169watts
13v/10ohms = 1.3amps or => 13v * 1.3A = 16.9watts

You just beat me at my own game with equations I have memorized. Good point, as usual.

[THEARCHITEK]

okay i have the same problem i guess thats the light that shows up looking like a car with lights on?? something like that on the dash? .... could it b possible that mine is because of the led lights i got on the corner? ... all my lights are working fine too

[LynchburgCSI]

Originally Posted by THEARCHITEK

okay i have the same problem i guess thats the light that shows up looking like a car with lights on?? something like that on the dash? .... could it b possible that mine is because of the led lights i got on the corner? ... all my lights are working fine too

LED corner lights in the rear might cause it. But it could be something else.

[RU2CHKN]

Yeah LED's in the rear could cause it I had the same problem when I installed LEDs for my tails. It wouldn't trigger the dash light if you got the LED's in the front of your car

[91boz]

Does your Camry have abs? Last weekend I was bleeding my brakes and had the tires off and noticed the the brake light on the dash was on. They stayed on until all of the rims were put back on.

I think this was due to the abs pickup on each wheel. If it doesn't sense a wheel it triggers the dash lamp.

Just a thought if you have abs brakes.

[ajkalian]

Originally Posted by 91boz

I think this was due to the abs pickup on each wheel. If it doesn't sense a wheel it triggers the dash lamp.

Just a thought if you have abs brakes.

That's too funny. Only some Engineer Bureaucrat would come up with something as stupid as that.

So let's see if I get this, your wheel falls off, and they figure you need a light on the dash to light up to tell you that your wheel fell off ??

Most people should be able to figure it out without the light, but as they say, you can never be too careful.

.

[LynchburgCSI]

Originally Posted by 91boz

Does your Camry have abs? Last weekend I was bleeding my brakes and had the tires off and noticed the the brake light on the dash was on. They stayed on until all of the rims were put back on.

I think this was due to the abs pickup on each wheel. If it doesn't sense a wheel it triggers the dash lamp.

Just a thought if you have abs brakes.

The ABS system is just rotational speed sensors on each wheel. Theres NO WAY it can tell if a wheel is on or off. That post is complete bull.

[73sport]

Originally Posted by :)

........
They stayed on until all of the rims were put back on.

I think this was due to the abs pickup on each wheel. If it doesn't sense a wheel it triggers the dash lamp.

......

Originally Posted by Comedian!!!!!

That's too funny. Only some Engineer Bureaucrat would come up with something as stupid as that.

So let's see if I get this, your wheel falls off, and they figure you need a light on the dash to light up to tell you that your wheel fell off ??

Most people should be able to figure it out without the light, but as they say, you can never be too careful.

.

Maybe some have Nano implants and play a hi-tech game of Peek-Abuuu w/the wheel? Hey, are you still there?

Wheel flew off my old Ford once. Watched it pass me i did. . . When you touch the brakes it makes cool flat spots on the rotor as SPARKIES Fly everywhere. If only I had idiot Light!