Deep into the weeds with the Door Lock Module (original)

[burch]

Hey everyone -

Decided to finally take care of my doors and locks that sometimes worked correctly. Started by taking out the latches, cleaning them, and performing a "wedgectomy" on all 4. Did a lock and latch procedure on both sides, and the doors have honestly never latched better or easier than they do now.

I previously modified the DLM to have the inline 10Amp safety fuse on the large power wire. Even with the old locks at about 80% efficiency, the DLM worked for a while, but would blow the 10A fuse every now and then. To improve the reliability of the system, I performed the "Elvis DLM mod" (http://www.teslorean.com/assets/uplo...Module-mod.pdf, if you're unfamiliar), using components equivalent to what Elvis has called out in the document. I also purchased new relays for the DLM and installed those as well. I have also examined my door lock solenoids, which are in great shape, move freely, and are unburned inside.

Wouldn't be posting this if everything worked correctly

With the doors open, and the latches locked, I attempted an unlock from the passenger side internal button. Both doors unlocked. I heard the relays click and the 10A fuse blew. Changed the fuse, tried again from the driver side. Same result.

Even with the fuse blown, I was able to determine the following:

1. The relays are assuming the right states when lock/unlock are pressed. They are staying in those states after the press, and not pulsing (I believe this is the correct behavior)
2. If I disconnect one door's electrical connection to the lock bellcrank, just to test the other door, I still blow the fuse. Doesn't seem to be one door or the other.
3. My inline fuse holder is one with an LED indicator. Interestingly, the indicator stays on (with the blown fuse) nearly all the time.

I've checked the resistance of all the resistors, the capacitors and the diodes/rectifiers (as much as possible on the board). There are no bad solder joints, and I'm not getting any resistance across the solder connections.

Any ideas on what I can check/test next? Obviously a Digital DLM would correct the issue as well, but it seems I'm not all that far off with what I have. Thanks!

[Bitsyncmaster]

Your unit may have a longer timing than most and if so that could blow a 10 amp fuse. I seem to recall each solenoid draws 10 amps but since the time on is so short that 20 amps does not blow the fuse. I would try a fuse without the LED but a 15 amp. fuse should still protect if the relays stick. The problem with the OEM and lockzilla units is they use a large capacitor to create the timing on the relays and that makes them open slowly and burns the contacts.

[burch]

Your unit may have a longer timing than most and if so that could blow a 10 amp fuse. I seem to recall each solenoid draws 10 amps but since the time on is so short that 20 amps does not blow the fuse. I would try a fuse without the LED but a 15 amp. fuse should still protect if the relays stick. The problem with the OEM and lockzilla units is they use a large capacitor to create the timing on the relays and that makes them open slowly and burns the contacts.

That may be the issue. I did try a 15 amp fuse and ran into the same problem. How high should I go?

[burch]

After more testing:

15A fuse - successfully unlocked doors, blew
20A fuse - successfully locked doors, blew
25A fuse - successfully unlocked doors, stayed intact, but appeared to hold solenoids in one place. Could not lock doors until power was disconnected.

[Bitsyncmaster]

I think the OEM controller times the solenoids for about 1 second of on time. The LockZilla was much shorter (about 0.1 seconds). Can you time how long the relays stay engaged. If you replaced the relays with higher resistance coils your timing will increase. The LockZilla used much lower resistance relays which is why the timing is so short.

[burch]

Thanks, Dave! I'm going to pull the module and just do some quick bench tests to look at the relays. I don't know for sure that they are disengaging.