DDM Issue?

[Hg M75]

A few years ago a couple of my door actuators were starting to getting lazy in my '04 sport, so I bought 4 new ones from Ford and replaced all 4. Recently I noticed my drivers door would unlock but not lock by the switch, the remote or the auto lock. The only way to lock the drivers door was manually push the plunger at the top of the door down. It would unlock no problem by remote, switch and by the interior door handle. Thinking I had a bum actuator in the drivers door I bought another from Ford but the problem persists. Only thing I can think of left is the drivers door module. Since the drivers door has it own relay in the module separate from the rest of the doors its my thought that the relay for the driver door gets the most use due to the two stage unlocking compared to the others. Anyone else have something similar happen? Any fixes like a resolder job for that relay?

[mustangeddie]

Had the same issue with one of mine changing the ddm fixed the problem.

[BAD MERC]

Mine does it too. All unlock, all lock except driver door. It used to be sporadic and now that it's a thing I might just chase down the bad relay and do a writeup. Or install my spare module.

[jaywish]

I have the same issue and replace the actuator last year. I guess the DDM is a generic Panther part and at least not MM specific?

[Hg M75]

BAD MERC, that would be awesome to do a write up. I'm very happy to fix things myself and this seems problematic enough based on the replies here. If you dig into it please let me know, appreciate any insight.

[mustangeddie]

I have the same issue and replace the actuator last year. I guess the DDM is a generic Panther part and at least not MM specific?
I'm pretty sure any 03 & up Crown Vic or GM are the same. Part# from one I took out of an 04 is 3W7T-13C791-AA.

[Hg M75]

That is the same part number on my '04.

[jaywish]

Does this work with engine anti-theft or just keyless entry?

Also tasca shows 03 3w7z15k602aa Eddie shows 04 is 3W7T-13C791-AA I believe either would work.

[BAD MERC]

I spent about 2 hours probing and testing the board of my new vs old DDM and the main relay seems to be ONE large multi-contact relay ass'y that does lock/unlock/trunk release. Using a test light I found the relay coil triggers to effectuate all three functions. I made a drawing with a legend and although one DDM works perfectly and one still won't lock the driver door - I still have found NO output differentials between the 2 units. That being said I can assume the lock button is reversing polarity using pink/yellow or pink/green positive momentary outputs from the L/U switch. So this is a rest-at-ground circuit. It appears that maybe the driver lock motor has lost a ground path. Although I didn't check for the presence of power or ground at rest in either switch position at the actuator.

There comes a point that time and resources are worth more than just purchasing a used DDM, programming your fobs to it, and programming your new favorite keypad code.

I think I am going the latter route. I fear that invasive testing could damage the one I have waiting to install and end this once and for all.

[mustangeddie]

Does this work with engine anti-theft or just keyless entry?

Also tasca shows 03 3w7z15k602aa Eddie shows 04 is 3W7T-13C791-AA I believe either would work.As far as I can tell it's only keyless entry.Somewhere in my mountain of stuff I have one from an 03 also if I can find it to check part#.

[mustangeddie]

There comes a point that time and resources are worth more than just purchasing a used DDM, programming your fobs to it, and programming your new favorite keypad code.
.Kenny , Iirc I didn't have to reprogram the fobs only thing I remember for sure is the keyless entry code changed but is printed right on the ddm sticker.

[BAD MERC]

Kenny , Iirc I didn't have to reprogram the fobs only thing I remember for sure is the keyless entry code changed but is printed right on the ddm sticker. That could very well be. My remotes weren't needed due to the extensive Clifford security installed and I programmed them to my Town Car because they weren't being used.

When I replaced the Smart Junction Box in my Taurus when it was new it came with two new remotes and a new code card. I wasn't sure if the DDM and SJB were that closely similar.

[Hg M75]

I appreciate you diving into it. I was hoping for something a bit more obvious/simple to correct the issue, along the lines of a solder touch up (sorta like the over head console display) but it doesn't appear that is the case. Now to hunt down a known good unit to swap in....nothing like looking for used 21 year old electronics and hoping for the best.

[Hg M75]

I've pulled the trigger and ordered a used DDM off Ebay and am wait for it to ship to me. It'll either fix the issue or I will have wasted $80. By nature I have a rather curious "why did this fail" mindset, I still want to solve the mystery. Will update when the "new" part gets here.

[Hg M75]

"New" (used) DDM came in today, plugged it in and it worked like a charm so far. Its crazy how nice it is to have 4 working door locks again, forgot how convenient power locks are as simple as they may be. Its the simple things, hopefully this fix lasts.