ML 500 lift gate
https://mbworld.org/forums/4941206-post5.html
Thanks,
If the other doors lock, then the CL relay k20 is OK.
I wonder if the system may have to be resynchronized with new actuator?
Didn't have a chance to check centeral lock relay..... I thought a relay isn't like a fuse, a fuse is good or bad, no gray area. A relay doesn't work that way.
Thanks...
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Your doors lock, so relay k20 is good. That same relay locks the tailgate - no sound or movement there during locking means you have an open circuit in the tailgate lock actuator circuit. It only takes one break to cause this, anywhere between F1, X18/1, M14/7, and back through X18/1 to F1 and relay k15. The most likely places are the moving parts - k15 (which you haven't clearly established is good) and where the wires pass between the roof and the tailgate. Repeated wear could rub through the insulation or cause breakage. A corroded connector is less likely.
Last edited by DrX; Oct 1, 2013 at 07:16 PM.
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Note: During this episode with tailgate, I've had the cargo compartment lamp shut off because auotmatic control feature stopped working, lamp would stay on continuously. I switched back to auto control position last evening, to check if that feature is operating since replacing actuator/handle assembly. It isn't, lamp remains on & is not switched on & off by opening or closing the liftgate.
Thanks...


If you ground the grey wire from the handle assembly, you can test that the actuator is working.
Last edited by DrX; Oct 1, 2013 at 09:42 PM.
Thanks again...
The story of my life... I always start replacing the hardest to get to and most expensive part, if that doesn't correct the problem, work down from there.
Thank you....
In hindsight, your initial description was that of a faulty lock.



