13

If it is a 21W/5W bulb, then it has 2 filaments of different brightness. The 5W filament is for the side/tail light for night driving. The 21W filament is for bright illumination when you press the brake pedal. Image copied from ToolStation


8

The fact that the light bar lights up means that it works. If the fault is consistent, I'd be more tempted to look for the fault at the brake pedal - where the switch for the light is. As your existing brake lights work correctly, next step is to see whether they use the same switch, as per @Brian's comment. It may be that the LED bar has been wired in ...


8

After much deliberation on going to repair shop, I figured I would at least poke around as it could not make anything worse. Here was the problem. The negative terminal wire soldering point was loose. I fixed it this way: Unplug the LED array. (Pictures to come) Video of removal process here on youtube Remove the rear plastic shroud(with a few upward ...


7

Taillight - Generic term that could refer to any part of the assembly or the bulb. Context required. (i.e. "your taillight is cracked" = lens, "your taillight is out" = bulb, "insert the bulb into the taillight" = forward shell, etc.) Taillight Assembly - The entire taillight, including the lens. Strictly speaking, this excludes bulbs. A manufacturer list ...


6

The parking lamp/headlight switch applies power or ground so the circuit would be open if you were testing with the switch off. Same with the turn signals. The tail lights are on separate circuits. They don't share a ground. Does the car have an aftermarket trailer harness? If not your going to have to remove panels and visually inspect the harness for ...


6

The tail lights on this car look like: (image source) The outer assembly is the one on the quarter panel: The inner assembly is the one on the trunk: I'm 99% sure of this, but note that it is the result of a bunch of Google searching, and generic product pictures on parts sites make finding a clear image confusing. If somebody could confirm this that'd ...


5

My mom's Prius HID bulb died (under warranty) so she took it in to get it replaced. The dealer replaced one of the bulbs and it was a completely different color than the original. I finally bought her two new bulbs from Amazon and replaced them for her because it was so bothersome. In a situation like that it is definitely worth it to replace both at the ...


5

Its fairly common for these to burn out sockets for the bulbs, and even often on both sides at the same time. The socket can be removed asa separate piece, and it is fairly likely melted and/or burned


5

I'm going to answer this in a general way because for someone to tell you what the wires mean, they would need to follow this procedure, or have access to detailed wiring diagrams for your car. You'll need a multimeter for this, and you'll have to take apart the brake light as if you were changing the bulbs so you have access to the bulb sockets. I'm ...


4

If the tail lights were hot during the swap you may have broken the filiments. Bumping a bulb that is on or been on recently can cause the filiments to fail. Remove the bulbs hold them up to a light and see if the filimant is intact.


4

The most common way to handle this will be rubbing compound and preferably a power drill or buffer. If this is a tail light it is likely a plastic of some kind. You can polish out minor surface scratches with rubbing compound and a buffing wheel. This of course depends on if this is a scuff or what most would call a scratch. If the depth is significant ...


4

I finally got this figured out. The housing inside the actual tail-light assembly had become deformed, I guess due to heat, thus keeping the light-bulb housing from making proper contact with the tail-light assembly. A new tail-light assembly fixed the issue. Thanks, everyone, for your help with this issue. UPDATE: Recently, the same thing happened on ...


4

A good service manual will have extensive wiring diagrams and possibly troubleshooting procedures and connector locations. With that and a multimeter, you can easily track the problem down. I prefer factory service manuals over Haynes / Chilton / etc, but they're not cheap. Looks like the one you would need would be $150 from Helm. If you can verify the ...


4

I'm assuming that you are testing the brake bulb voltage with the brakes actuated. There is high resistance somewhere in the circuit causing a voltage drop. For example lets suppose there is 10k ohm of resistance in the brake light switch. When the bulb is out and the switch is activated there is no current flow. A good meter has 20M ohm of resistance and ...


4

Its a mixture is tradition and function. Red has been used to signify "Stop" much longer and in many more applications than just motor vehicles. Stop and Do-Not-Enter signs are used everywhere. Possibly, although I can not confirm or cite a source, in history blood was used to mark doors and entryways that should not be entered and therefor the red color ...


4

Remove the tail light bulb then hit the brake and see if it still blows the fuse. If the brake light works, then the combined bulbs is too much for the fuse. Check the wattages of the new bulbs. If it still blows remove both bulbs. If it still blows you could have a short in the housing. Re-install the old one to make sure you didn't introduce a short in ...


4

Blue Green is the indicator wire for the left rear, blue brown for the right rear. Assuming USDM.


4

The ABS light is an indicator of an error caught by the ECU. It usually is an error for a defective ABS sensor or a related brake issue. It's difficult to tell what exactly it is without reading the error code. Some specific problem might be fixed by reprogramming the ABS module, others won't. Depends on the issue and the year of your 528i. Once you get the ...


4

As @fred_dot_u said, test to see if the lights will go off if you raise the brake pedal up with your hand/foot. If so, it's likely that your brake pedal switch needs to be adjusted, or less likely it is defective. Adjust your brake pedal switch. https://www.yourmechanic.com/article/how-to-replace-your-brake-light-switch-by-spencer-cates Making an free ...


3

I've had a similar problem before and it turned out to be the socket for the bulb was bad. I'd start with inspecting wiring that you can see, but proving wiring "good" is pretty much impossible (and replacing it is likely to be a major chore). It might just be cheaper/easier to try and replace the socket first and see what happens. Sorry I can't be more ...


3

Break out the multimeter. Start at the bulbs. Verify the ground is good and then and work your way back towards the fuse box looking for an open as long as the wiring is accessible (Have a friend / brick depress the pedal). Assuming you haven't found the trouble spot, move to the fuse box and go the other way. If you're lucky the problem will be where you ...


3

If you are looking to figure out which wire goes to which, an easy way to figure this out is to have a source which produces 12vdc and has the two leads for (+) and (-) with probes attached, plus a pad and pencil to mark down what is what. After you have your 12v source and other supplies to get started, take the bulb section out of the housing so it looks ...


3

Blowing a fuse is a pretty good indication of a short circuit. If you have a DMM (digital multi-meter) try some basic tests: With the fuse out, read between the prongs of the fuse socket and ground (a nearby screw or other bare metal) with the meter on a DC Volts scale (20 VDC is common) to identify the hot side of the fuse. Once you know which side is hot, ...


3

You may be able to extract the screw by "drilling" it out with a left-handed drill bit running in reverse (counter clockwise). If you're in the US you can get a relatively inexpensive set from Harbor Freight. This YouTube video shows the technique. The original recess for the driver will give you a good center for the bit. Before starting I'd spend some ...


3

Have you damaged the start of the thread - easy to do on plastic threads. Dress the end of the thread with a small file and make sure it is clean, then it will normally go in.


2

Factory repair manual is a bit sketchy about it, but here what it says (translated from Russian version): Put the roof in the intermediate position (I suppose, somewhere in the middle between fully open and fully closed). Cut out (?) and remove the carpet (1 on the figure). That cutting out bit puzzles me. Maybe, just pull out from under the trim? Partially ...


2

If one headlight dies and gets replaced then the new lamp is usually brighter then the old one. This bothers me and I usually replace both. I keep the working old lamp and the next time a lamp fails I replace it with that, resulting in two slightly dimmed headlights.


2

I had the same problem, turned out to be the green / white wire on the right rear cluster. Simple easy fix.


2

You're exactly correct in that thinking (I replaced the bulbs in my old Volvo once and it caused it to think they were out because the bulb was slightly different (these weren't even LED's; just a different filament or connector or something, I forget; no tolerance at all on that circuit). I don't know if there's a standard way to fix this (other than use ...


2

If you look in the trunk near the taillight you will find some plastic screws that hold the carpet in place. Using a flat head screwdriver remove them by unscrewing them or prying them out. Moving the carpet should reveal the mounting bolts for the taillight. It will most likely require a 10mm deep socket to remove the nuts. Disconnect the lamp sockets from ...


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