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

[DMC-81]

Clarification from above: I'm manually testing the relays, and they are sticking in their position.

Yes, in my research, sticking relays were also a common problem. It's good to ensure that your solenoids are not shorting, but many times the relays need to be changed. That's why I mentioned the part numbers. I rewound the solenoids as they were my root cause, and although my relays weren't sticking, I replaced them anyway.

I disagree with David T in that the ONLY cause of the fuse blowing is a burned solenoids. A short anywhere (for example, a short in the harness at the top of the door) can also cause it.

You can check with Toby at DMCNW to see if he has any in stock.

[burch]

These are brand new ones from Toby, I'll contact and see how he wants me to test. Thanks!

[David T]

Once you burn up the contact points on the relays they will tend to "stick" or not open quickly anymore because of the arc. The relays burn up because of the excessive load caused by the shorted solenoids. You can dress the contact points on the relays but that is a very short term fix. The better fix is to replace the relays and rewind the solenoids. Disconnect the solenoids and see if you still blow the fuse. If youl do it is possible you have a shorted wire going to the solenoids but more likely you just have burnt solenoids.

[Elvis]

Use the relays I suggested and they will work fine.

the original BOSCH units tend to stick. Don't know how others work.

But still - rewind the solenoids, they can not be measured by resistance, only by inductivity.
10 A fuse burns - solenoid bad.


Side note - I am testing at work a circuit that draws up to 100A for a short moment.
small cheap relays will stick after a few switches. The one I use to replace the BOSCH relay
in the ECU now switched around 10000 times and still works fine.
Sombody back then said you need an insulated relay filled with gas...well the ones that stuck
after a few cycles were insulated ones - so I stay with the ones that I've been using for more
than 10 years.


Thanks for reading my old how to - that I never replaced with the updated one with the 10A fuse
and the remote instructions.