Still trying to get my intermittent remote door locking problems resolved.
This is driving me nuts !!!
Just spend north of $1000 bucks with an independent repair shop here but problem still persists.

Have already searched multiple online forums for a solution to this problem. Found that a number of people had similar or identical problems in the past, but no final root cause analysis or remedy was ever published.

HOPE THAT SOMEONE CAN POINT ME IN THE RIGHT DIRECTION.

Here are the symptoms of the problem:

* remote locking function works completely intermittent
* works more reliably at night / when dark outside
* works sometimes just from driver's door, but not on passenger side or trunk
* works sometimes from driver's door AND trunk, but not on passenger side
* occasionally when using the key in driver's door lock the red or green LED indicator
lights stay on for a long period of time (overnight).
* when re-seating the connector on the IRCL controller sometimes everything works for
5 minutes
* key stopped to operate trunk lock, but red or green LEDs are flashing
* when using remote the red LEDs sometimes flash longer than the green ones

Here's what has been done already (failing to resolve the problem):

* replaced key batteries in original key and synchronized the remote
* bought and synchronized new key (on recommendation of repair shop)
* replaced all fuses in the car and cleaned contacts
* cleaned connector contacts of all accessible control modules (including IRCL
controller).
* polished all external remote sensors
* repair shop checked car diagnostics, but no clear result

Questions I have:

* do the symptoms point to a defective IRCL module?
* do the symptoms point to other potential connectivity issues - which ones?
* is there a way to check if the IRCL module is bad?
* if IRCL module is bad, can it be replaced with a used one from another car or is the
module coded to the specific car?
* any other thing I should have checked?

THANKS MUCH IN ADVANCE.

Possibly the infrared receiver(s) is the cause of the problem.

For $1000 you could install several aftermarket systems! and they can operate from 100 feet.

__________________
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M.B.DOC, thanks much for the tip ... I think you got a point with the sensors - did some more extensive testing yesterday after it got dark outside and the remote locking system worked flawlessly without a single miss - during daylight completely intermittent.

I know that MB doesn't offer the sensors separately - you only can get them together with the complete door handle (= very expensive).

I will keep my eyes open for a set of good used ones.

Now, do you happen to know if the sensors have stayed the same throughout the whole R129 model life cycle or have there been any changes between the early and late cars?
Also, I'm assuming that MB did use the same sensor assemblies in other car models (cost optimization) as well, do you know which ones?
Someone told me W124 and W140 up to 1996 - can you confirm this?

Muchas Gracias.

Are you sure about not being able to just replace the sensor. I was able to replace one sensor in the drivers door last year. Car was R129-1993 300SL.

__________________
Tony

1993 300SL
2005 SLK350
1999 SLK230 (SOLD)

AJG382, thanks - that's interesting.
Did you get the sensor replaced at an authorized dealership? May I ask what they charged for the sensor cube ?
I was told by a MB dealer that you can get the sensor only with the complete door handle.

I work for an independent dealer who sells German cars, So I get parts at cost.

The parts on the invoice were Infered Pick Up and some clips that hold the power seat controls to the door. Cost was $166.00 The clips were most likely a couple of bucks.

I did this in March of 2008. If I remember correctly there were two part numbers. One for the driver's door and one for the passenger door.

__________________
Tony

1993 300SL
2005 SLK350
1999 SLK230 (SOLD)