LDCM acting up... fix or replace? Cheapest option available?

[Cobra4B]

Driver's side door control module is acting up more often now... used to be once in a blue moon. Is this something expensive that can be fixed by a 3rd party like the ECBM, or is it a non-repairable unit where the fix is replacement?

Is there any mechanism or part of the component that can be cleaned to allow it to lock/unlock the door properly?

Thanks,
Brian

[Cobra4B]

Anyone?

[Eagleeye]

Symptoms ??? I've had broken wires to act like bad modules too [ in the flex. boot] between chassis and door. Most door modules are sealed units but I'm not sure about C5. But...give us more specifics

[Y2Kvert4me]

I've not had to deal with them on my car, but I do know it's about a $100 part to replace. No programming to the car needed, just plug 'n play.

I believe the door control modules are little more than a few relays inside, and these are what crap out in them.

This is pasted from a CF thread....It may help you.


Ok boys and girls, step right in, class is about to start. I am sure most of you guys have read posts about windows not working or door locks not working properly. Today, we are going to learn how to fix those pesky door lock and window problems. At least as far as the control module goes. This is not to say there could be other problems, but this is how to fix the weakest part of the whole system, a bad relay. What I want to do is show you how to get to the control module and then identify which relays are for what function.

Required tools: Flat blade screw driver, number 15 and number 30 Torx drives, a fork like prying tool , (sorry I don’t know the proper name of this tool), soldering iron, solder sucker, and solder.

Step 1: Today, we are working on the passenger door. Remove the little plastic cover plate behind the door pull. It pops out with the screw driver.
Step 2: Using a number 30 Torx drive, remove the two screws that holds the door panel to the door.
http://img100.imageshack.us/img100/4451/pict03741kw.jpg
Step 3: Using a flat blade screw driver, pry up on the window/door lock control panel. Lift up from the front as shown. Remove wiring connector and set the control panel somewhere safe.
http://img100.imageshack.us/img100/9279/pict03736rb.jpg
Step 4: Using a flat blade screw driver, pop out the plastic piece that surrounds the door handle.
http://img100.imageshack.us/img100/2400/pict03722mh.jpg
Step 5: Now, we are ready to remove the door panel.
http://img180.imageshack.us/img180/3396/pict03593pm.jpg
Using the fork like tool
http://img100.imageshack.us/img100/7471/pict03691ua.jpg
start at the rear of the door panel where the two halves meet.
http://img100.imageshack.us/img100/4645/pict03711wx.jpg
Insert the fork like tool in and pry the panel away from the door. Work your way around to the front top part of the door panel. There are 6 pins that fit into little sockets in the door. Now, lift up on the door panel and remove it.
http://img100.imageshack.us/img100/8333/pict03680bv.jpg
Step 6: Use a number 15 Torx drive and remove the two screws that hold the door control module in place.
http://img100.imageshack.us/img100/5076/pict03674iq.jpg
Step 7: Remove the wiring connectors that attach to the door control module. Now, look at the edge of the enclosure and pop open the tabs that hold it closed and remove the circuit board.
http://img100.imageshack.us/img100/732/pict03661iy.jpg
http://img443.imageshack.us/img443/1552/pict03649wm.jpg
http://img443.imageshack.us/img443/5779/pict03659lz.jpg

[Y2Kvert4me]

Look at this last picture and it will show you which relay control the windows and door locks.
http://img377.imageshack.us/img377/9103/pict03601xg3.jpg
1997 to 2000 model


http://img99.imageshack.us/img99/6162/newdcmps8.jpg
2001 to 2004 model

Step 8: After pre-heating your soldering iron, use the soldering iron and solder sucker to unsolder the 5 pins from the relay you want to replace. Everything on the circuit board is coated with a plastic film, you will have to use a small knife blade, or small blade screw driver, and cut around the relay before you try to pry the relay off of the circuit board. I found the same film on the solder side of the board as well. If you scrape off some of that plastic film before you apply the soldering iron, you will have better success at unsoldering the pins.
Step 9: After the relay is replaced, re-assemble everything. Be sure to note where the wiring connectors plug back into. The plastic housing is marked for the correct color of the wiring plug.

The Digi-Key part number for the door relay is 255-1240-ND and you can find it at Digi-Key - 255-1240-ND (Manufacturer - JSM1-12V-5) (http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=255-1240-ND). Last time I looked, they had 1400 in stock.

The window relay is a Mouser Stock number is 551-EP2-3N1S, and they sell for $3.93 each plus shipping and maybe tax. Here is the link:
551-EP2-3N1S (http://www.mouser.com/Search/Refine.aspx?Keyword=551-EP2-3N1S)

I hope this helps you guys that have intermittent door locks or you can hear a clicking sound but the window doesn’t go up or down. From start to finish, this project took me about an hour. Heck, it took me longer to do this write up than it did fixing my door lock. But, hey, that is what Corvette Forum buddies are for.

Hope that helps...

:cheers:

[Eagleeye]

BTW...pulled DIC codes ? You should have a couple if this is a repeat problem. Most likely a B.... or a U.... This info will also help

[Y2Kvert4me]

BTW...pulled DIC codes ? You should have a couple if this is a repeat problem. Most likely a B.... or a U.... This info will also helpDoubtful.

The usual malfunction is the doors simply don't lock or unlock when commanded...that specific activity is not monitored by the BCM so there is no code to be triggered. There is no feedback loop unlike the infamous coulumn lock. :D

Now that this topic has been brought up, come to think of it my pass door sometimes doesn't unlock when commanded. It may take me a 2-3 tries before it does. That would be typical of the unlock relay contacts failing within the RDCM.

:cheers:

[Cobra4B]

^ That exactly what happens, oh and it does trip codes... I get LCDM and RCDM codes when the locks don't work on the first try. They all eventually lock/unlock but don't always work when commanded.

When I install my mod-red door panels I'll tackle this isssue.

[Lowcash]

I have a LDCM sitting in the garage. I bought it accidently (was looking for the door switches, but read the description wrong). As far as I know it works. I can let it got for $60 shipped. Let me know if you want it. :thumbs:

http://i320.photobucket.com/albums/nn357/l0wcash/car_stuff/DSC03996.jpg

[Cobra4B]

Sean... I can't remember what year your car is. If it's 2001+ I'll take it. PM me your paypal.

[Lowcash]

Sean... I can't remember what year your car is. If it's 2001+ I'll take it. PM me your paypal.

Dooh! ... My car is a 2000.

[Cobra4B]

Oh well :)