Windows, Sunroof, Locking, Wipers

[Sansouci]

Hey team,
What is your opinion of periodically spraying all contacts for relays and fuses, both the blades and sockets with electronic contact cleaner?

[shogun]

I do it with contact enhancer. BMW even had a service info to do that: Stabilant 22A Electrical Contact Enhancer Model: All BMW
Complaint: Connectors which carry low current are more likely to form deposits which affect the resistance of the circuit through the plug connector. Depending upon the particular circuit these deposits can cause malfunctions and consequently activate warning lamps and check control indicators.
Remedy: Part replacement can temporarily stop the problem. If the connector is the problem then without disconnecting the connector measure the resistance of the circuit running through the connector to make sure the connector has a high resistance. A good resistor will have close to 0 ohms resistance. Visually examine the male and female terminals in the connector housing by removing them. Look at the integrity of the wire crimps, and in some male terminals the integrity of the weld of the male pin to the terminal. Then reinstall. With a zero residue electrical contact cleaner liberally spray the male and female connectors, and allow the air to dry. Apply Stabilant 22A to both male and female terminals so they are saturated, and reconnect the connectors while they are still wet. When the Stabilant 22A dries it will leave a thin coating of polymer film which is conductive between mating surfaces, and is non-conductive between adjacent pins. It can also prevent the formation of more harmful deposits.

[nk1221]

To bring this back from the dead for anyone in the future. My car turned out to have a pretty severe water leak in the trunk for some time before my ownership.

Water flowed down into the back seat and damaged the carpet and cause some serious corrosion in wiring.

In late 2016 I found multiple factory rubber capped crimped connections under the rear fusebox that were laying on the lowest point of the area (where the water would pool). These bundles were red power with red rubber caps and others with multiple different colors at the crimp and yellow rubber caps. I never looked into the diagrams to figure out what junctions they were exactly. I found some incredibly stiff wiring and started cutting back from the crimps to find that all of the shiny wire had become black/white and stiff.

I cut these wires back until I ran into clean copper. Some followed across the rear floor up to the passenger A pillar and other towards the driver pillar before clearing up. I cut back inches at a time and then replaced the run with a new wire. I went through probably 60 feet of new wire.

Buttoned everything up and boom. Everything was working. Mirrors, windows, lights, sunroof.

Since then I have replaced the carpet in the car and put over 80k miles on the ol'm30 with the auto trans.

For the people that are having electrical issues, I recommend a good multimeter and checking things throughly.

Many thanks to Shogun and others for the massive collection and knowledge on these not so common machines. I live for BMW wiring diagrams now and get excited when I have to bring them up again.