[estoril_335]

The 'left rear signal malfunction' popped up in my car. All turn signal bulb still working. When I turn signal left, the light blinks faster than usual. I turned off and turned on the car again, it went away, signal work normal again.

The malfunction come back again sometimes when I shut off the car and while driving.

Is this mean something about to go out soon.

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[Billfitz]

You have an intermittent connection fault on that bulb. Rapid blinking happens when the bulb is not functioning, either due to a bulb fault or a wiring fault. Since you posted the same question in a thread about connector failure you already are familiar with that.

[328iX]

Low or zero resistance in the bulb will cause the rapid blink, replace the bulb and recheck.

[Billfitz]

I'd be looking at the connector before replacing the bulb. Intermittent open circuits aren't unknown in bulbs, but they're rare. I think I've seen it once in the last 50 years.

[chazmink]

Could be a bulb filament that intermittently makes contact. I'd try a new bulb to start.
Good luck.
Charlie

[airbug1009]

I experienced this in my previous E60. The rear signal light is exactly like what you experienced. The cause of this is due to the plastic mount of the wiring melted which results in poor connection. Try unplugging the rear light connector and check.

[chazmink]

I thought more about this. On my 2010 535i I had the taillight assembly replaced under warranty because a contact had failed. I don't recall if it was caused by heat, moisture or a combination of both. The dealer didn't seem surprised by it.
Good luck.

[snoskiguy]

I have heard that dielectric grease can help and to look for any melting at the plug.

[Billfitz]

Grease will prevent corrosion, but I don't think that's the primary issue. If it was it wouldn't be the same ground conductor burning out in every case. They have one ground conductor for all the bulbs in the lamp. If only one bulb is on no problem, but if more than one is on that single ground conductor probably isn't large enough to handle the current. That creates heat, and repeated heating leads to eventual failure. I had been considering LED rear bulbs anyway, switched to them after I became aware of this. They draw maybe 1/5 the current that standard bulbs do, so no heat.

[Rebound]

It happened to me. The ground pin in the molex connector isn't thick enough, so it's prone to burning. This makes the connection intermittent, until it eventually fails.
The top two pictures show a good connector. The third has the blown ground. It's possible to run your own ground wire, bypassing the connector. That's what I did.

[sprvlln]

Originally Posted by Rebound

It happened to me. The ground pin in the molex connector isn't thick enough, so it's prone to burning. This makes the connection intermittent, until it eventually fails.
The top two pictures show a good connector. The third has the blown ground. It's possible to run your own ground wire, bypassing the connector. That's what I did.

Thanks for this! My connector looks exactly like the third picture. Could you elaborate on how you ran your own ground wire to bypass the connector? I'm looking at how-tos but am curious on how you worked around the connector itself and where you ran the ground wire to.

Thanks for the info.

[sygazelle]

Originally Posted by sprvlln

Thanks for this! My connector looks exactly like the third picture. Could you elaborate on how you ran your own ground wire to bypass the connector? I'm looking at how-tos but am curious on how you worked around the connector itself and where you ran the ground wire to.

Thanks for the info.

I had this problem on my F30 and using this Youtube video, I learned to fix it myself. It's not difficult if you follow the instructions in the video carefully.

I've read on this forum where people try to fix by replacing the connection but deciding to not go to the trouble of adding the extra ground wire. If you decide to to this, I recommend that you add the extra ground wire. It's not difficult.

When I fixed mine, I failed the first time. I didn't get the new probes seated all the way into the new connector. The second time I was careful to make sure they were all the way in and locked.

Check out this link.

https://www.youtube.com/watch?v=7gpKoeNzKws

Good luck!