Whole set of electrical problems

[marsgorski]

I have an 87 325E coupe that has several electrical problems. I thought I would write one post for all of them since I imagine that some of the problems might share the same cause.

The problems are

1. When locking the car from the trunk, only the trunk and the passenger's door lock. The driver's door doesn't lock (it used to a few years ago). The same goes for unlocking.
2. When I try to lock/unlock from the driver's door nothing happens. This problem has existed at least since I bought the car (9 years ago).
3. The antenna stays up the whole time and doesn't want to go down when I turn the key to the off position, even if I give it a gentle push. This problem is fairly new, a few months old. (fixed by replacing old fuses)
4. The turn signals work, but the left one flashes at faster pace, as if it were trying to tell me that the bulb burnt off. But the bulbs work. This problem is several years old.
5. The break light in the rear windshield stays on even after I release the pedal. However, with a very gentle pull on the pedal with my foot the light does turn off. This problem is several years old, possibly since I own the car.
6. Tachometer doesn't work. Speedometer was also not working but that got fixed by installing another used one.
7. Cigarette lighter does not work (fixed by replacing old fuse)
8. Side view mirrors do not move.

None of the fuses seem to be burnt. Battery was replaced recently (less than a year ago) and alternator was replaced 6 or 7 years ago. I have an aftermarket stereo but (I think) stock speakers. No amp, subwoofer, etc. I am interested in installing an amp and subwoofer but I'm worried it might make other electrical components worse. I know nothing about car audio though and my fears may be unfounded.

Any advise about where to begin, what components to check, etc. would be greatly appreciated!

[richardodn]

1&2. You have a mechanical problem with the driver door lock mechanism. It could be any number of things. I recommend going through the central locking troubleshooting guide in the ETM on page 5126A-0. You can find the ETM online at http://wedophones.com/BMWManualsLead.htm
3. Check for power at the antenna. Constant power is on the red wire. You should see batt/alt voltage at all times. If not replace fuse 28 and check again. Make sure the ground wire is in good shape. The white wire is turn on. When it sees 12V the antenna goes up. No voltage and antenna goes down. If all this checks out, there's a fault in the antenna itself that is usually solved by a replacement mast.
4. Common reasons for this are the wrong lamps in the front turn signals, bad grounds, corroded sockets and corroded connectors. See if any of the lamps are dimmer than the others and start there.
5. Replace the brake light switch on the pedal.
6. Faulty tach and/or mpg gauge are usually due to a bad SI board in the cluster. Do you have any problems with mpg gauge and service interval lights?

[marsgorski]

Thanks! I looked at the troubleshooting guide in the ETM and followed the first few steps. It tells me I need to replace the Driver's door lock switch, which makes sense. I looked at the part online and seeing a picture of it jiggled my memory a bit: A few years ago (maybe 6 or so) I had an auto electric replace that part. He said there was another part (don't remember which one) that needs replacing, but there was no way for me to get the part in time and he was able to improvise something. The door locking was fixed but only temporarily, it failed again after a few weeks. This makes me think that the problem may not be the door lock switch but the other part he improvised. I guess I will have to take a look, but with my lack of knowledge about these systems I may not notice anything. Nevertheless I will take a look and unless I notice something I will replace the switch (which I hate to do since they're expensive).

On another front I also replaced fuses 10, 11, 12, 21, 27, and 28 (some of them were replaced about a week ago, others were replaced today). None of them were burnt, nevertheless the result was a fixed the antenna, as well as a fixed cigarette lighter (which I had forgotten to add to the list of problems).

I've also added a new problem I just remembered: sideview mirrors don't move.

I will report on the progress as it happens.

1&2. You have a mechanical problem with the driver door lock mechanism. It could be any number of things. I recommend going through the central locking troubleshooting guide in the ETM on page 5126A-0. You can find the ETM online at http://wedophones.com/BMWManualsLead.htm
3. Check for power at the antenna. Constant power is on the red wire. You should see batt/alt voltage at all times. If not replace fuse 28 and check again. Make sure the ground wire is in good shape. The white wire is turn on. When it sees 12V the antenna goes up. No voltage and antenna goes down. If all this checks out, there's a fault in the antenna itself that is usually solved by a replacement mast.
4. Common reasons for this are the wrong lamps in the front turn signals, bad grounds, corroded sockets and corroded connectors. See if any of the lamps are dimmer than the others and start there.
5. Replace the brake light switch on the pedal.
6. Faulty tach and/or mpg gauge are usually due to a bad SI board in the cluster. Do you have any problems with mpg gauge and service interval lights?

[richardodn]

The usual fault with the side view mirrors is the internal clutch. When that fails it will move in one direction only. (e.g. side to side not up/down) But the motor still works. If neither works at all, I'd suspect the switch or power supply. Fuse 19 is the supply circuit. That circuit also supplies power to the interior light timer control. What the time control does is:

1. Turns the interior lights on for 6-8 seconds when the driver door handle is pulled up. Test it by pulling the door handle up with the car locked so the door doesn't open. The switch in the door handle is usually the problem when this doesn't work.
2. Keeps the lights on for 6-8 seconds after the driver door closes.

[superj]

maybe the wire bunch in the door jamb of the driver's door has some breaks? that door gets opened and closed a lot more then the rest so those wires get a lot more flex work hardening so maybe one has finally broken?