I reached out for help with this a few weeks ago and the threads are gone.
So, my passenger side front turn signal does not work. I replaced the bulb and it works when the headlights are turned on but not as the turn signal. When I engage the signal the flasher arrow in the dash beeps very quickly - seems like a warning. Fixing bmws is new to me. Any sugestions would be greatly appreciaterd.
You have a bad bulb or a bad ground at the lamp assembly.
The bulb has two filiments inside, one for the running/parking lights and one for the turn indicator. The filiments are connected inside on the ground side. The turn light can then get a ground from the running light side, but this ground goes away if the headlamps (parking lamps) are on. Since the running lights are a different size electrical load than the turn indicators, the turn indicators blink at the wrong rate on the affected side of the car.
You say the problem is on the front, but it could be either the front or the rear. The light that does not come on is easy to find, but the light that blinks fast can be caused by either end of the car. You need to clean the grounds for the lamp housings and make sure the bubls are in good shape. One test is to swap the bubls from left to right, if the bulb is the problem, the trouble will follow. If the car is the problem (bad ground connection), then the trouble will remain.
One of your turnlight bulbs is bad, most likely. It may be the one in the passenger side back, not the front. Check all your lights. Usually when your signal flashes fast like that, it means one of the 4 turn light bulbs is dead.
You might want to look inside the sockets. The outside of the socket is the ground, the two small posts on the contact in the bottom are the voltage sources.
I'm not sure how your car is built, but my 3 Series cars have a large connector serving the lamp housings, and the ground for the left and right are daisy-chained together, then grounded to a common point on the chassis (body). Since you have one side of the car working right, and the other side not, then I suspect the ground is okay and the socket itself is corroded. Personally, I'm still on a defective bulb, but the socket is the next thing in line. If you had a bad ground, odds favor both sides of the bulb not operating, which brings us back to a bad bulb.
The most common mistake in fixing lighting problems is over-thinking the issue. This is especially true when a bad bulb is replaced by another bad bulb. The problem is usually the bulb, then a grounding problem at the bulb itself, then a grounding problem in the wiring harness. The further (physically) one gets from any particular bulb, the larger (more lamps) the problem becomes. A poor ground for a harness should cause more than a single lamp to fail, and a single failed lamp will have a localized problem.
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