Press the brake and the tail light element goes out.

After owning a used vehicle with no warranty and for maybe 300 miles of driving the left rear brake light failed. There are two bulbs on the left side. One is the turn signal and the other has two elements and one comes on when the lights are turned on and a second element that comes on when the brake pedal is pressed.
Quite a few miles later we get a light alert on the dash that another or the same light was out. It turned out to be the same left brake light bulb. The existing one on the right side is 1157 and the replacements we got were 1157LL. The pack had two bulbs and we tried the spare bulb and still the left brake light fails. The tail light works but when the brake is pressed the tail light goes off and no light on the left side.
I moved the right side bulb to the left and get the same result.
This is curious as to how it happened. A failure after hundreds of miles and then the new one last maybe 3 more weeks and now bad. It is obviously (or not) not the bulb. I can go to a parts yard and pull a replacement rear light assembly with a 3 day warranty.
I'm not clear why the left tail light works and that specific element goes off when the brakes are applied.

We can drive with one brake light and if we are stopped by police no issues. But if that officer sees us again at a later date and the same bulb not working they might give a ticket at that point.

Nothing is seen as being crossed as far as wires, no wire that might have a naked spot touching metal, etc.

Any ideas on why this is happening. We will not take it to a mechanic under any circumstances. That is not a solution. Thanks.
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JohnBusiness Consultant (Owner)Commented:
A light bulb (or other resistive device) can only draw the current it needs. So it is not likely an overcurrent situation

the new one last maybe 3 more weeks and now bad.

The bulb runs very hot and an 1157 draws a couple of Amps.  

So my guess is that there is a loose connection, therefore an intermittent flow of current (on / off) rapidly to the hot bulb. This will wear it, I think
Any body work done to the vehicle, especially the left rear?

I take it the running light on the right side stays lit when brake light is on.

I would suspect a poor ground on the left side.
JohnBusiness Consultant (Owner)Commented:
Poor ground would create the intermittent condition, I imagine
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nickg5Author Commented:
No work on the left side, but when the left light went out the plastic housing had come lose (it just snaps in) and the hot bulb touched plastic and melted a little spot. This I think caused the bulb to go bad. The new bulb lasted many miles.

The right rear light works normally. The new bulbs work properly on the right side.

A pull a part replacement will be easy and / or I can rewire it if needed.
If it is a poor ground and between the engine compartment and before it reaches the trunk area it may be hard to locate. I currently do not have a ohm meter. I can use a tester I have to locate the hot wires and the ground wire.
JohnBusiness Consultant (Owner)Commented:
the hot bulb touched plastic and melted a little spot. This I think caused the bulb to go bad.

That will certainly burn out a bulb.

Check the wiring when you can for good continuity (Hot and Ground).

I noticed the rear light assemblies in my cars have wired plus and negative and then ground (physical ground) is additional.
"The tail light works but when the brake is pressed the tail light goes off and no light on the left side."
To be clear... when you have the lights turned on, the left rear running light is illuminated as you would expect.  When you hit the brake pedal, the left rear running light goes off and the left rear brake light stays off.  Correct?

Does the left brake light work when the running lights are off?

I'd check with a voltmeter (free to $10) to confirm what is going on with the two hot wires that go to the bulb.  One should be hot when the lights are on, both should be hot when the lights are on and when you hit the brake pedal.  Make sure you are connecting the second lead of the voltmeter to a good ground when you do the test.

I'd do the test above with and without the bulb connected.  I'd also test the voltage of the ground connection as close to the bulb as you can easily get under those conditions.

I can imagine one scenario where you have a poor connection on the hot side somewhere.  When it's just the running light on, the drop over the resistance of the poor connection isn't enough to keep the light from being bright enough to notice.  When you  hit the brakes you have both light elements connected, which will try to draw more current.  That may drop enough voltage that you can't see the lights.  The voltage test with the bulb in place will demonstrate if this is the issue or not.  I'd check how the lights are fused.  Specifically, are running lights on one fuse and brake lights on another, or are they fused as right running/brake on one fuse and left on the other?  If you see an issue with the voltage test when the bulb is in place and not when it is disconnected, check back at the fuses.  There may be some corrosion there causing the issue.  Removing and reinstalling the fuse may fix it.

The last paragraph is one possibility of what could be the issue, not a real diagnosis.  The voltmeter tests will give a much better clue.

"A failure after hundreds of miles and then the new one last maybe 3 more weeks and now bad."  That's really not a fair description.  It sounds as if the first bulb failed, but you don't really know how long it had been used before you bought the vehicle.  The second one didn't actually fail from your description.  The issue appears to be other than in the bulb.  You've put a known good (from the right side) bulb and it shows the same symptom.  It would have been a good test to put the questionable bulb from the left side in the right side to confirm that the bulb is also good.
David Johnson, CD, MVPRetiredCommented:
You have a wiring issue. If you have a European tail light system which has independant brake and turn signals it is a simple fix. break the existing connection and run a wire from the right side and connect it to the left.

If the running light goes out then there is a short somewhere along the line.. Wiring harness issues are a pain to troubleshoot (expensive) and repair. The replacement harness isn't that expensive but labor intensive to replace.
There will be a ground connection to the body at the rear for the brake lights.
nickg5Author Commented:
It's the left housing though I see no wires touching each other or touching metal or any wire that might be 1% naked.

I moved the right side light housing to the left side and it worked, tail light and brake light.

I'm going to a pull parts yard this weekend and try to get another one.

A new wire from the right side to the left is a good idea given by David.
JohnBusiness Consultant (Owner)Commented:
There is (likely) an intermittent fault in the housing or the nearby wiring. That could cause the surges that wears on the bulb filament and burns it out.

Make sure if you add a wire that you do not create a double ground or double hot.
nickg5Author Commented:
If there is a surge it is not blowing the element. The bulbs are good and swapped from side to side for testing.
JohnBusiness Consultant (Owner)Commented:
A failure after hundreds of miles and then the new one last maybe 3 more weeks and now bad  <-- I interpreted this as a filament failure.  

If not, then the intermittent would be an open circuit causing no current to the bulb.
nickg5Author Commented:
filament failure.
If not, then the intermittent would be an open circuit causing no current to the bulb.

The bulb works fine when moved to the right side.
The right side housing works fine on the left side.
But neither have been tested on the road for many miles which I will.
JohnBusiness Consultant (Owner)Commented:
There is something going open caused by vibrations
David Johnson, CD, MVPRetiredCommented:
an intermittent can either be a short circuit or an open connection.
nickg5Author Commented:
This won't be resolved soon. I can not visit a parts yard for a new left rear light assembly until Feb. 16th or 17th. The elements in the bulb are not breaking.

Running a wire from right to left is a good idea.

I can trace the wires under the lower door trim and tape the wires to try to eliminate a short or bad connection.
Have you reviewed a wiring diagram for that vehicle?
"Running a wire from right to left is a good idea.
I can trace the wires under the lower door trim and tape the wires to try to eliminate a short or bad connection."

I'm doubtful either will help with your specific problem.  From what you have described, the problem is in the left light assembly.  That's based on the reports that the symptom follows the housing, not the location.  If the problem was in the wiring then you'd see the symptoms on the left side regardless of which light housing was being used.

I would be suspicious of a poor connection (corrosion is often the culprit) in the bulb socket, in the rear socket where the wires connect, or in between if there are any connections (sometimes with rivets).
nickg5Author Commented:
I have the 185 page manual and pages 92-96 show the diagrams but the PDF is not letting my copy paste the pages to here.
I think this left assembly may have been replaced before. There is a blue dot (from a marker) on it. This is what pull parts yards do when you wish to enter with your own part to search for a match and they put such a mark on parts you are buying.
nickg5Author Commented:
The issue is not worth trying to figure out all this mess.

If the problem follows the light housing, it is very unlikely that the wiring is the issue.  The wiring diagram isn't very helpful about what is inside the housing.

The connector on the housing, the bulb socket, and any connection points in between are the most likely culprits.
The grounds for the light are at the rear but maybe shared between the sides.
I agree the assembly housing is most likely the issue.
Could disconnect the assembly and use a test light to confirm power for the lights.
nickg5Author Commented:
Well how many vehicles have this problem. There are millions of cars on the road and I happened to get behind a Kia and when they put on brakes their right tail light went off. My car is a Toyota. So this caused me to pause and think that maybe it could be the bulb in some way or two different brands of cars have the same bad connection or short.
I'm going to get a new left light assembly on Saturday but there is a good chance the models they have on the lot are different because my vehicle is 3 years older than the ones they have and the part may not be compatible.
JohnBusiness Consultant (Owner)Commented:
The only time this ever happened to me was on my first Volvo 1975.  The manual transmission was removed for service and upon replacement, the wires leading to the stick shift were interchanged and I got screwy lights at the back. Fixed the wires and all was well. 10 Volvos and 44 years later, no issues like that again.
While not really common, it's certainly not unheard of to have connection issues inside a taillight assembly.  A common cause is moisture getting inside and causing corrosion.

I would expect that a bad connection is almost certainly the issue.  A short is likely to cause your fuse to blow.

As far as compatibility goes, there are many auto parts vendors online that can answer the question.  Put in the particulars of your car and see what the part number is for the assembly.  Change the particulars to those of one in the lot and see if it uses the same part number.
nickg5Author Commented:
Ebay: Used OEM brake lamp failure module. Fits some Toyota Camry
Important note: If you have a dash light on indicating that you have a brake light out, yet your rear lights work fine, replacing the brake light failure module will almost NEVER resolve the dash light.  Instead, you have a bulb or wiring issue.
Depending the technology bulb sensing is done by comparing the impedance of the bulbs in the sensing circuit, usually both bulbs have to be changed ( new bulbs same package )
nickg5Author Commented:
The two parts yards did not have my model and the oldest Camry they had was 1993 and I knew that before I left. These yards usually only keep vehicles going back maybe 25 years. Finding my model in one of the yards is dismal.

So I'll do some testing on the power wires, ground, etc. when the rain leaves here over the weekend.
nickg5Author Commented:
Surprise. One of our you pull it yards lets you get an email alert when your vehicle is in the yard. I had little hope for a 1990 Camry. The oldest I saw at the two yards was 1993 and the parts were not the same. An email arrives and I was surprised so I went there and removed the left and right light assemblies. Both showed corrosion and rust. With little chance of ever finding a 1989-1991 in these yards in the future I got both L and R. I tried the left one and the turn signal works fine and so does the tail light. When I pressed the brake no light. The only hope at that point was the bulb was bad. I replaced it and the brake lights do come on.

I'll choose solutions based on content.
nickg5Author Commented:
Replacing the left assembly and new bulb

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nickg5Author Commented:
I'm not getting a chance to mark the four comments as very helpful. Why?

John suggested intermittent flow and only time will tell how long this bulb last in the new assembly.
As far as the grounds these assemblies are all plastic, no metal touching metal and no visible ground wire.

Hopefully the left side and right side might be remotely (1%) wired the same so that the extra right I bought could be used on the left.
It rained alot and when I opened the trunk to begin working on the left side, water came flying out of the right side light. I can likely drill a hole in the bottom so water escapes.

If it fails again in the next ?? days / weeks then back to intermittent flow, bad ground, bad connection somewhere between the steering column and the rear.
nickg5Author Commented:
It says only 50 points per and that was not my intention.
How to I edit that?
JohnBusiness Consultant (Owner)Commented:
You can look down the left side and apply whatever points you wish.
JohnBusiness Consultant (Owner)Commented:
Thank you for following up and your kind comments.
"bad connection somewhere between the steering column and the rear"
If the symptom follows the housing (fails on whatever side the questionable housing is installed) then it's NOT a problem in the wiring outside the housing!  If the symptom stays on the same side, regardless of which housing and bulb are there, then it's outside the housing.  Pretty straightforward.
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