Center Brake Light has no power LCM fix?

[gornlordunoboggle]

So after replacing a cracked and broken center brake light in my 2003 2.5 the new one wouldn't light up.
I bench tested it with power and ground the new light is bright and perfect.
Tested the Brown ground wire at the harness - perfect
Tested the Yellow and Black power wire from the LCM no power.
Removed the LCM and tested continuity back to the 3rd brake light - the yellow black wire has 0.01 ohms back to the light so I'm certain my issue is the LCM.

I'm looking for some advice.
1. How awful is it to replace the LCM - does it need to be programmed to the car whats the module name does it need other modules sync'd etc
2. Does the LCM have short circuit protection for this circuit that could be reset?

I gave a quick college try checking for fault codes in INPA & ISTA D but nothing is there and I reviewed a guide for another bmw on resetting frm failure counters with tool32 but I need e85 specific info to truly attempt that.

Anyone have any experience in this area?

[bigwinn]

Just check

The connection on an aftermarket high level brake light unit to the existing loom is at best ‘difficult’

I don’t think that’s an lcm issue at all

[gornlordunoboggle]

I fully agree aftermarket connectors are garbage. Mine actually didn't even fit so I chopped the connector off my old unit and soldered it onto the aftermarket lights harness. I'm certain the power wire from the LCM is ok because while If I apply 12v to the yellow and black wire at the LCM connector the 3rd brake light lights up bright.

I've already repaired all the broken trunk wires as well so unfortunately I'm certain this is an issue with no power coming out of the LCM for the 3rd brake light. I should mention all other lights work properly so I know I don't have a brake switch or input issue.

I guess a silver lining is maybe I can get Auto headlights if i change out the LCM

[bigwinn]

You can swap the lcm no major dramas but will need to code it to the car to remove the tamper dot?

[gornlordunoboggle]

Thats awesome. I'm planning to put a used LCM in. So Plugging it in it will work right away besides the tamper dot?
Ive done some googling but what program would I use to marry it to the car winkfp?

[bigwinn]

Spot on matey-

And yes winkfp will reprogram the unit

[BumpyZ4]

You could also back probe the LCM connector with the connector connected and see if it is putting out 12 volts.

[gornlordunoboggle]

Figured I'd update this and pass on some info to the community. I got a used LCM off ebay. same year and same hardware & software numbers on the tag. I used PA soft to program it.
PA soft is one of the trickier programs to install but worth it. Its extremely intuitive and easy to figure out & considerably faster than ista. It also uses different hardware than ISTA or INPA/ BMW tools so to use it you need to buy the hardware. Its cheap - way cheaper than paying someone else to do it.

As soon as i plugged in the LCM everything worked- 3rd now lighting up as it should. but tamper dot on the odometer and air bag light too.

In case anyone else ever needs to install an LCM here's some tips & step by steps.

Before you install the LCM get PA soft working and familiarize yourself with its very basic scan/clear dtc functions.
When you first load up pa soft it immediately shows the vehicle info displayed from the IKE and the LCM everything from mileage vin upholstery code and paint codes. They should match with the original modules installed. It wouldn't hurt to take a picture of this screen. When a module is replaced it will show all the donor vehicles info under that module.

Before you unplug the original module -Go to the units tab and select LCM in pa soft. then go to the coding button. Under that there is a button that will open a window full of boxes with check marks - I forget which one but you'll know when you find it and theres only a handful of choices. The boxes are selecting for which light faults to trigger the warning on the dash and under what conditions on the side are xenon head light settings. take a picture of this with your phone as once you install the new LCM you'll want to have this screen match what it is now.

Now you can install the new LCM.

When you load up PA soft it should show your vehicles info in the IKE side and the donor vehicles info in the LCM side.
As you work through the steps below everything should match up piece by piece. You're done when its all matched and no dtcs are setting like : IKE dtc's for - Mileage discrepancy between IKE & LCM, and SRS dtc's for mismatched body code.

Use the units tab and select LCM
First set the algorithm for communicating with the LCM. PA soft has has a chart to help you know which to pick. if youve got a complete match excellent, I only had partial matches but that worked.
Then under programming - click write odometer. this will fix dtcs with being out of sync with the IKE & is the first step to fixing the tamper dot.
Then shut the car off and disconnect everything wait a minute or two.

Key on again and set it all up - open pa soft - unit tab lcm - programming - Write the FGSTNR this will have you enter the last 7 digits of the VIN.

the Tamper dot should now be clear, but when you load PA soft your upholstery /paint codes / engine codes will still be wrong.

This is fixed by Transferring the vehicle order it calls this FA. I believe this is under the programming tab as well but you will see FA on the button you want. Then you have two choices: match the IKE to the LCM or LCM to the IKE.
Obviously you want to do this right, if you're replacing the LCM then you load IKE info into the LCM (IKE ---> LCM) don't screw this up, You might be able to fix this by reinstalling the old LCM and moving its FA back onto the IKE and trying again but its better to just not have to get into that mess at all.

Now you're almost done. What I had left to do at this point was go into coding - there's a button i forget which one but you'll know it opens window full of boxes and check marks - if you did it before you can now consult your photo from earlier and make sure it matches - on mine I had to turn off Xenon head lights setting since my car doesn't have that.

Air bag light still on dash?
I'm not sure why this isn't talked about more but on my 2003 e85 once the air bag light comes on and the code is stored in the IKE the only way to turn it off is with ISTA +. I've tried INPA/PA SOFT/ & AUTEL Scanners - only ISTA+ reliably clears the IKE fault codes to shut the light off once the problems are solved.

Wait why isn't my ista/bmw tools obd2 connector working? In setting up the PA soft hardware, the latency and com type can become changed. you can fix this by opening the device manager finding your connector and changing its settings back to what is recommended for your application for my bimmer geeks connector it was com type 1 latency 1. (pa soft is com type 4 latency 16 i think). Once you've done that INPA is the quickest way to check your connector is working the title page when INPA is opened it shows connector: yes/no & ignition position: on/off if those are yes and on with the key on and everything plugged in then proceed onto ITSA +.

The ISTA+ steps are simple - start a session - vehicle id & test - scan for faults - clear the mismatched body fault codes from the 4 air bag satellite modules. it will ask you to shut the ignition off following the fault code erase. then push cancel and unplug it all. when you flip the key back on the air bag light should be on for a couple seconds then turns off and stays off - that means the system is good.

One final thing - you can use an Auto headlights lcm in a vehicle without that from factory. the LCM I put in was equipped with Auto headlights setting - my car never came with that but what happens when you install one in a car not equipped with light sensors etc is it defaults to lights on when key on and lights off when key off when the switch is placed in auto.

Hope this helps. Cant believe I did all this just for a 3rd brake light...