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      01-14-2019, 04:17 PM   #1
Nickon
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Brake light and turn signal malfunction

Hey everyone,

Just wondering if you have ever had this issue. My turn signal and brake light (left side only) will go out randomly. Then all of a sudden it works fine. I don't think it can be any of the lightings in the car itself, or it wouldn't work all the time. When the turn signal malfunctions, the headlight and the side mirror blink really fast but the tail light will not.

Has this happened to anyone? I have an appointment with BMW but would like to know what is going on with my car. Thanks for the help everyone!
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      01-15-2019, 11:15 PM   #2
cfm56d7b
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Is your car under warranty? Hopefully yes. The dealer will find the root cause.
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      01-28-2019, 03:05 PM   #3
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Quote:
Originally Posted by Nickon View Post
Hey everyone,

Just wondering if you have ever had this issue. My turn signal and brake light (left side only) will go out randomly. Then all of a sudden it works fine. I don't think it can be any of the lightings in the car itself, or it wouldn't work all the time. When the turn signal malfunctions, the headlight and the side mirror blink really fast but the tail light will not.

Has this happened to anyone? I have an appointment with BMW but would like to know what is going on with my car. Thanks for the help everyone!
I think I know the cause. This happened to me as well.

There is a molex-type connector which brings power to the brake/turn signal assembly and bulbs. The ground pin isn't thick enough, and as the car vibrates, connectivity is reduced so much that it overheats and burns, like a fuse. The problem is a little difficult to spot, because the wire itself looks fine, but the pin inside the connector is cooked and missing.

A dealer will replace all the parts under warranty, of course. Outside of warranty, the solution is to get a small amount of insulated wire and solder one end directly to the metal inside the housing, creating a giant and very solid ground plane. You snake this through the water/humidity drain cap in the housing. Then, crimp or solder a spade connector to it.

Next, you'll cut the ground wire leading the burned pin in the Molex connector. Crimp or solder the corresponding spade connector. Reassemble the tail light, attach the Molex connector, attach the spade connectors, and you now have a connection that's much more robust than stock.
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      01-28-2019, 03:53 PM   #4
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It happens a lot, there's a few threads about it. We know it happens a lot because dealers keep the socket repair kits in stock. They only do that when they know from experience that they'll need them. Seeing a picture of a burnt out connector was all I needed to convince me to switch to LED, as they draw about a tenth the current that regular bulbs do.
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      02-03-2019, 05:14 AM   #5
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Having the same problem. Thanks for the info.

Does anyone know the part code to the repair kit ?
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      02-07-2019, 06:28 AM   #6
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same thing happen to me

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