2006 R50 5 speed, 130,000 miles. The rear wiper turns itself on while the car is parked without a key in the ignition and the wiper switch in the off position. In order to turn it off I needed to put my key in the ignition and ran the engine, made sure the front and rear switches were off. After shutting down the car and locking it, the wiper began operating again. The battery seems good, it started right up, and it is 4 years old. Any thoughts on what might be the problem? TIA

 

I found a Youtube video that attributes this sort of behavior to a bad ignition switch. Thoughts????

 

So the wiper would run around the clock if you didn't pull the fuse (F17) or disconnect the battery?

Does anything else operate that shouldn't with the key removed? Front wipers, mirrors, HVAC controls etc?

 

Bc1 would be my first guess.

 

BCM or wires going to wiper are corroded.

BCM - if that goes bad it causes the lights and other things to have a mind of its own. like a low battery. Its usually not just one thing, most of the time.

Check the wires and connection at the rear wiper motor itself. The tips of the wiper spray also leak, its part of the rear wiper system and i have seen those leak back inward on the motor.

https://www.ecstuning.com/Search/Sit...h/67636932013/






Then ignition: https://www.ecstuning.com/Search/Sit...h/61326913965/

If the ignition goes bad its also hard to start. It will turn over half the time.

 

Another thought is the ground, a lot of them are joined into combs at various locations, a bad ground on one or two wires on the comb due to breakage or corrosion will cause wierd issues.

 

Excellent questions - The wipers would operate with key removed. Next I will see what happens with keys in and fuse pulled.

 

Thank you. I really appreciate the suggestions. I would not have thought of these. I will inspect these as well.

 

Voting BCM and/or rear wiper relay.
For illustration in case you don't yet have your copy of Note that panel source (via fuse F17) is always hot, even with key removed.
Up top the black outlined box labeled I01142 is the relay. BCM is the dotted box down below.
Under normal circumstances, pin 7 should read 0V / ground when the wiper is switched off and / or key removed from the car. Since the wiper continues to operate, it should now read closer to battery voltage. Pin 9 would notionally read at / near battery voltage if the BCM was behaving, lower / closer to ground if the circuit was active (pulled to ground by the misbehaving BCM) and feeding control current through the relay to switch the relay - and wiper motor - ON.
Short answer:
Either:
(1) the relay is stuck ON because it's malfunctioned / failed;
(2) it's stuck ON because the BCM is misbehaving or
(3) the relay's control circuit is unnaturally shorted to ground somewhere / somehow. Could be at the connector, the BCM, or somewhere in between. By total coincidence, both the fuse panel and the BCM are located in vulnerable locations, basically sitting right under the potential waterfall deluge if your tiny, fragile rubber sunroof drain hoses let go inside the A-pillar, another epic BMW engineering achievement.

The bad news: if it's a ground/ short somewhere you get to go find it and correct it.
Worse: if its the BCM, you'll need to have it overhauled or replace it with a known good one. Expensive, and you get to wait for the part to arrive.
Biggest day ruiner of all: if it's the relay, you get to pull and replace the entire fuse panel because like its evil twin, the fuel pump relay in cars built after 9/2005, the rear wiper relay is integrated (permanently soldered) into the fuse panel's internal circuit board. Why? Because BMW is Satan, and doesn't want you working on your own ****ing car when in their infernal opinion, you should be bringing it to the Stealership service bay where you will pay them an obscene amount of money to replace a part that normally costs $7 and ten minutes of your time in your own driveway on most other cars. That's why.

 

Thank you for the input, I really appreciate it. I have not had a chance to investigate further yet, hopefully this weekend. I have a total of six cars and you'd think that there will always be several working cars. Not so. There are six times as many cars that seem to need repairs simoultaneously. And a house to prep for sale.

 

I finally started to dig into the wiper issue. More fun - the passenger side front foot well is a few inches deep in water. May be related to the wipre issue, may be a significant, albeit red herring. In any event, need to dry out the carpet and floor pan. One rhetorical question - why the Heck does automobile carpet, which is explosed to all kinds of elements, contain more sponge than carpet(?). Discuss.

 

That one is easy.

1: noise abatement
2: so the floor doesn’t have to be level and thus be used for air vents, electronic modules, etc etc

 

loose / disconnected / broken A-pillar sunroof drain hose most likely the culprit, very common issue and yet another example of BMW engineering corner-cutting f**kery. Fortunately not difficult or expensive to fix; many threads and vids on it.

 

Update - finally got to further inspection of the car (I am usier than I want to be). The sun roof water channels are intact. I sent air pressure and water down them to make sure they work prperly and they do. If they hade obstructions they're clear now. I found what may be the cause of water in the driver's foot well, see pic. This drain (screen) was completely clogged with pine needles (I need a much bigger garage). I uncolgged the rubber screen thing and vaccuumed that entire cavity in the pic. Sent air then water through it and now it drains freely. I am awaiting delivery of the Haynes ManuaI for my Mini to identify any other drains that are hiding from me. I have not yet gotten to addresing the rear wiper issue but it seems likely that the water in the footwell casued the problem. Once completely dry I will inspect all the wires and connnections and the BCM. It seems likely that a water logged BCM is the cause. The wiper motor and connections seem fine. Although I have done nothing yet except drain the footwell, the wiper issue itself is fixed but I'll have to address the BCM next. I briefly researched "BCM" and to my delight it evokes nightmares of replacing the immobilizer in my Miata. I chalked up the immobilizer issue as the result of almost a quarter million miles on the clock. The MIni BSM issue is my own fault. SInce I can onlhy garage two cars I will regularly check the varios drains on all the vehicles. Once again thank you all for the help. I'll follow up with new developments as I go along. Great info from a great group of car guys!

Don't remember the exact location and orientation of this styrofoam.

Drain at the bottom was clogged.