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Discussion Starter · #1 ·
I posted this on your fellow E39 forums to no avail. This is really a weird one. My car has auto locks enabled. Pulled out and drove abt. 5 miles and out of no where the passenger side lock starts going up and re-locking by itself. At the same time, it sounds like a motor slipping like what you used to hear just before your electric antenna would go out in years past on American cars. sounds like plastic teeth slipping/grinding/broken; motor/gears slipping and "whirring". At first it was a slow whrring and the lock would go up and down. Then it got much faster and lock stopped moving. then lock button quit moving, but whirring kept on-- on passenger's side. Immediately after, the driver side starts same behavior except after the lock went up and down a couple times and the whirring kept going and getting faster (like whatever teeth were left were now broken) the lock itself stopped actuating, but the whirring just stayed on. Now, it sounds like both sides are staying on and whirring/grinding/drone is coming from both sides of the car and is now hard to pinpoint exactly where noise is coming from. With sound hitting both ears now, it begins to seem like it is coming from console or dash area. Turning car off does nothing. Turned around and headed home after punching the center lock button few times to no avail.

I am now heading home and grinding is still happening. It must have been about 5 minutes by this time that the lock actuators (I'm guessing) are both growling away. I go to lower the driver's side window on the trip home and at last the sound stops (as soon as I go to lower the window). Get home w/o further incident, but when I push the center console lock button, the rear door locks act completely normal, but front locks make same whirring noise for about 2-3 seconds each and then stop. Front doors do not lock. I can push the front lock buttons down by hand easily and by pulling the door handles, the locks will pop up just fine. Pushing center lock button just produces a 2 second whine from each lock area and only rears will actuate.

Don't understand the sequence of how the problem started. Passenger side starts by itself...locks and unlocks a couple times and then whirring starts. Problem jumps to driver's side now in addition to passenger side and it locks and unlocks a couple times and then joins in perfect harmony with the orchestra on the pass. side! Using remote produces same 2 second whine, but if you push unlock on remote it will only try once and then you must push lock on remote next. If you push lock on remote or unlock on remote multiple times in a row, it will only whirr once. You must maintain sequence of lock/unlock/lock with the buttons as if the car believes it has locked and will only respond to the unlock command next. Help!
 

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Discussion Starter · #5 ·
I am fortunate to find someone so knowledgeable. Yes, this is with a 2002 540ia. Cold weather here and fact that car sat for awhile could mean battery was tad low, but it started the car fine and I was 10 minutes into the drive when it started. The noise seeming to com from the center console is really just that both doors now make the whirring sound in unison...kind a stereo affect where then the music seems to be centered in front of you. I am sure it is coming from each front door. Where is the GM located and how many gazillion dollars are we likely talking about here if you have an idea. Makes complete sense why fronts only are affected. Must have sent an unlock signal first to one door and then kept sending that signal even though door was unlocked until it stripped the actuator. Then it moved to the other side until it had destroyed that actuator too. So, I am looking at a GM and two door actuators...can't wait to see what that adds up to. Are the actuators a fairly easy DIY? Does dealer need to code GM? What all will be involved to get it back to "normal"?

Thank you so kindly for the excellent advice. I can try the battery disconnect if you think it might solve the GM fault. It seems to be sending normal pulses to the doors now, but actuators must be toast?

Bill
 

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Discussion Starter · #7 ·
Larry:

Your help has been invaluable. I believe the battery very likely was the cause as her 2002 has 90K miles on it and had the original battery which never failed to start the car even in the coldest weather, but it measured only 12.3 VDC on my fluke. I bought a new battery and wondered if I found a new module for the 540 with Xenons as she has if it would be able to bypass coding and just need key programming. From what you say, I will still need programming. If that is the case, does it really matter if I buy a used model from say a 2001 530 or a 2003 528? I only see mention of car needing module that matches the type headlights you have???


Also, as for the inside the door actuator, If you look at them on Ebay, they fall into one of two categories...one looks like a pack of cigarettes and only has a connector on it and the other has rods and such that it for sure is the rod with the lock button itself, a rod to hook-up the the inside door handle, and also looks like it has the cigarette pack-sized module also mounted to the steel plates with all the rods and linkage needed. I assume that is the part I stripped out, but what does the small cigarette pack-sized module do by itself?

Thanks again Larry- you have been exremely helpful. I hope with new battery that BCM acts correctly, but with stripped door lock mechanisms, I'm not sure how I can tell if it is working right. When I start and push lock button, it attempts to run the actautors for about 2 seconds and then stops. That seems "normal. It no longer runs on and on...

Bill :2:
 

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Discussion Starter · #10 ·
Great insight. So, for those who have done this replacement, in that cigarette pack sized assembly, what is inside there that makes that slipping, whirring, stripped gears sound? Is it just a small solenoid, gearset, or what is actually in that pack? Have either of you seen a diy that you think would be helpful? I am working long hours this week so I have not been about to tackle, but I have bought a new Duralast DL-49 battery which I hope may get the General Module to start behaving itself again. Assuming that it does, then hopefully just the two actuators took the hit. I just don't know what is inside that assm. that would make the noise like the lock is locking and unlocking, but yet the knob does not move whatsoever...the button at the door top.

Bill
 
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