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a faulty DDM should be ruled-out, the chances of two modules with the exact same fault is practically zero.
your DDM is working in every other respect, so it's software is likely not an issue.
the chances of 2 faulty mirror-motors (yes there's 2) is low, unless your supplier pulled a fast one, these motors are hard to break so it's likely not that.
Just ran some tests on collection of mirror-motors here, they're DC 12V, draw approx 40mA and their static resistance ranges between 50ohms and 250ohms.
for mirror-motor none rotation, it's either
not being powered i.e. no 12V - highly likely
jammed, but for both to be stuck i- very unlikely.
motors broken - very unlikely
just can't hear it - possible
Motor Tests
This quick and easy test will tell you if the motors are wired correctly, pull-out C4 the 10-way BLACK connector and measure the motor resistances as follows:-
i, Between C4 Pin-7 Yellow wire and C4 Pin-8 Light Blue wire, this should read as 4 above (left-right motor movement)
ii, Between C4 Pin-7 Yellow wire and C4 Pin-9 Light Green wire, this should read as 4 above (up/down motor movement)
If either/both have the resistances as specified (but not short-circuit) they should be turning, you may have to press your ear against the mirror casing as they are fairly quiet.
If there's no resistances its likely and issue with the wiring, remove the mirror-glass (easily done) and inspect the wiring to the mechanism inside, the motor gears as well.
fyi this is what a motor looks like, for scale its 1" in diameter and about 1.25" long
This is what a disassembled gear assembly looks like
This is what a broken gear looks like
Finally, there could be something odd about either the replacement mirror or the door wiring that's not come to light yet.
Presumably you've kept your old mirrors-arms for reference?
If so, perform the above Motor Tests on connector C4 for comparison, you could even plug it in to see if you can hear the motors turn. Even if the mirror-glass doesn't move, if you can hear the motors you'll know there's a problem with you replacement arm
Last edited by oceanbrave; Aug 26, 2025 at 11:41 AM.
Thanks. I like to think of myself as a good tech but the thought to at least try the old mirror
didnt come to mind. I broke free the glued mirror when I took it off. So if the motors work at all
ill know. I honestly don’t really care that the mirror doesn’t work. It’s the only thing on the truck
that doesn’t work other than drivers side lumbar adjustment. Again does nothing. Anything
‘related? All the seat adjustments work great. Just nothing from lumbar. And no noise of any kind.
‘would be interesting if related.
Speaking here without double-checking, but I'm 99.9% confident the lumbar+seat controls are on separate modules.
fyi I have completely reversed engineered the DDM to down to PCB layout, components, electronic schematics, functionality etc, everything except software.
Last edited by oceanbrave; Aug 27, 2025 at 07:51 AM.
