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E39 (1997 - 2003)
The BMW 5-Series (E39 chassis) was introduced in the United States as a 1997 model year car and lasted until the 2004 when the E60 chassis was released. The United States saw several variations including the 525i, 528i, 530i and 540i. -- View the E39 Wiki

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  #1  
Old 03-20-2013, 07:49 AM
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doru doru is online now
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LCM III - is it repairable?

For the 2001 + years e39, the part is called LCM III, I believe. It doesn't have the protruding heat sink. There 2 p/n:
One is for factory equipped HID lights: 61356961142
The other is for non-HID lights: 61356961141

I might have some issues with it. However, I was reding that these type of LCM might not be serviceable like the LCM II counterparts, where one would replace the VN750-E chip (was called Infineon Mosfet chip) - this is the new nomenclature (found at Mouser Electronics).

Can anybody confirm/infirm this? Has anybody attempted and repaired or failed to repair LCM III? I am really not looking forward to buy a new 500+ $ part, or finding a used one which will last God knows how long, plus the added headache of trying to re-code it (must find one with LESSER mileage than mine - which in itself is a chore).

More info is welcome. I might have it wrong.

Thanks
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  #2  
Old 03-20-2013, 08:25 AM
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bluebee bluebee is offline
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As you probably already know, there isn't much in the bestlinks under /lcm F3:
- How to repair (1) (2) or replace (1) your light control module & where to get new LCM chips (1) (2)

I will run an E39-only, title-only search for LCM III to see what comes up & report back.

EDIT: Your's is the only E39 post with LCM III in the title, so I'll be dropping the III & reporting back...

EDIT: Well, there are 75 hits for LCM in the title of an E39 thread - looking briefly at the metadata, none seem overwhelmingly canonical ... so I'll stick with what we have at the moment.
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See also: E39 Bestlinks & How to easily find what you need

Last edited by bluebee; 03-20-2013 at 08:31 AM.
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  #3  
Old 03-20-2013, 09:44 AM
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doru doru is online now
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I know the above mentioned links. they are all for the LCM II, which is fixable. I was reading somewhere that the LCM III is not. It said you can't even open the unit, but if you can, apparently it's a new technology applied that reduces the heat, and the Mosfet chips are dropped in favor of integrated electronic parts. Need confirmation if this is the case.
Thanks for your effort though.
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TMS underdrive pullies - Stewart WP - PSS9 - Beisan Vanos seals - Zimmerman cross-drilled & Akebono Euro - Deka 649 MF - 55w HID headlights - 35w HID foglights - Hualigan double din - ACS (rep) alu pedals - Euro central storage console - Breyton Magic Racing staggered wheels - M5 bumper - M5 steering wheel - Tint
Stable: e39, e53, e46 & Tribby
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  #4  
Old 12-23-2013, 05:51 PM
pleiades pleiades is offline
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Quote:
Originally Posted by doru View Post
I know the above mentioned links. they are all for the LCM II, which is fixable. I was reading somewhere that the LCM III is not. It said you can't even open the unit, but if you can, apparently it's a new technology applied that reduces the heat, and the Mosfet chips are dropped in favor of integrated electronic parts. Need confirmation if this is the case.
Thanks for your effort though.
My '99 528i has an LCM III as well. They are easy to open but I don't think anyone has documented servicing them in any way similar to the mosfet chip replacements that are possible with the LCM II.

I've come upon this thread though in search of cases of LCM III shenanigans and what folks have done in the way of DIY repair. So far, no luck.

Here's what has happened to my car....

A couple of weeks ago, we had a weeklong cold spell with snow and record low temps, dipping into the single digits and even as low as -4 F. (I know, not anything special, but for Eugene OR, it's about 20-30 degrees below our normal lows for this time of year.)

I didn't drive the car that whole time as we have a Subaru that came in very handy on the slippery streets and slopes around here.

Once the snow and ice had melted away and all the streets were back to normal, I decided to crank the bimmer and take a spin.

As I was fumbling around in the car getting ready to back out of the driveway, I noticed that my high beams were on. I looked at the light switch (off), flipped the turn signal stalk to see if it was stuck (nope), and then it dawned on me, this could be the first serious electrical gremlin I've experienced with this car.

Naturally, first I removed and examined the signal stalk. It seemed fine. I re-installed it, put the steering wheel back together, re-attached the battery and tried again. Same symptoms.

A few days later, I went out to the car and tried again, to see if I could identify some sort of pattern. It was worse. The issue started with the high beams. They would not flick on/off with the signal stalk but would turn off if I pushed the stalk forward into high-beam setting. (This was with the light switch off all the time....).

Just re-attaching the battery neg. cable and waiting a few moments was enough for the high-beams to come on, but then the lows (xenons with aftermarket ballasts) also began turning on (car off, light switch off). Additionally, the high beams (halogen bulbs) began to flicker on and off, as though somewhere in the circuit something is shorting out.

What I've done:
- Removed the LCM III. Another contortionist job in the passenger footwell.....
- Opened the LCM. (Pulls apart with some minimal prying/flexing of the casing around the connector sockets.
- Examined as best I can (no expert) for missing circuit board pieces and cracked solder joints. Nothing visually obvious.

I read a thread on M5board by someone with the same LCM version.

http://www.m5board.com/vbulletin/e39...-blinky-4.html

At the end, the poster returned to note that it wasn't his LCM at all, but likely a set of flaky xenon ballasts.

I'll throw up some pics of my LCM unit's board.








Last edited by pleiades; 07-09-2014 at 09:40 AM.
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  #5  
Old 12-23-2013, 10:31 PM
GreenTiger GreenTiger is offline
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FYI, LCM 3 was implemented in 9/98. Same time as VANOS.
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  #6  
Old 12-25-2013, 01:04 PM
pleiades pleiades is offline
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Incidentally, can anyone tell me what sub-version (c.XX) of this LCM III module I have? I suppose the information is on that yellow label in the pics above, but I don't know how to decipher it.

Or, is coding software the only thing that will be able to tell me?
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  #7  
Old 12-25-2013, 03:57 PM
scottjoh scottjoh is offline
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LCM III - is it repairable?

I have repaired the LCM III. Not that easy to work on, but, doable if you have the right equipment. The VND920 chips usually go bad so I keep a few around in case one comes in for repair.


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  #8  
Old 12-26-2013, 07:11 AM
pleiades pleiades is offline
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Quote:
Originally Posted by scottjoh View Post
I have repaired the LCM III. Not that easy to work on, but, doable if you have the right equipment. The VND920 chips usually go bad so I keep a few around in case one comes in for repair.
Mine doesn't appear to have any of those.
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  #9  
Old 12-28-2013, 05:20 PM
nomilk nomilk is offline
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Be careful if you change the LCM: as I changed it on my ex 523i, I discovered that the check control had no function more. I changed it with the original, and it came back...
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  #10  
Old 12-31-2013, 11:54 AM
scottjoh scottjoh is offline
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That's a different layout from the LCM module I've repaired. The LCM below that I repaired is from an X5. I just assumed that the E53 X5 and E39 5-series used the same modules just coded differently.
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