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Keyless Entry Handle Working intermittently - Solved
Lately, I've been noticing that my driver-side rear door handle "tap to lock" and "pull to unlock" are not working correctly. I'm used to getting out of the car and tapping the rear handle to lock as I walk toward the rear of the vehicle. Sometimes it seems to be inactive as it won't lock or unlock the car, even if I hit unlock or lock on the key to "wake it up" it doesn't always work. Usually, I have to open/close the door a couple of times and then it starts to work again.
I assume its nothing on the actual handle that fails, is there some sort of connector in there that I can start checking? I will try to scan the door module tonight and see if there are any codes.
Lately, I've been noticing that my driver-side rear door handle "tap to lock" and "pull to unlock" are not working correctly. I'm used to getting out of the car and tapping the rear handle to lock as I walk toward the rear of the vehicle. Sometimes it seems to be inactive as it won't lock or unlock the car, even if I hit unlock or lock on the key to "wake it up" it doesn't always work. Usually, I have to open/close the door a couple of times and then it starts to work again.
I assume its nothing on the actual handle that fails, is there some sort of connector in there that I can start checking? I will try to scan the door module tonight and see if there are any codes.
Replace main and aux batteries if older than 4 years.
If the problem still exists, the offending door handle may need to be replaced. Somewhat common failure for MB vehicles - handles need replaced at higher age/mileage.
So I went ahead and removed the rear door handle, the connector had a good amount of corrosion on it.... see pic below. Tried cleaning it but no luck. Now we have a bigger issue, I swapped the driver side front handle onto the rear to narrow down the issue to the actual handle, and that worked. But now when I put the "working" front door handle back on the front door, it no longer works...
I have two codes now that say there is a door handle fault for both driver side front and rear door, did I just ruin my front door handle too....
OK major update and probably a good PSA for anyone who has this issue in the future. I did some closer inspection on the door handle wires, there are hard kinks in the wire where it routes through the handle. After removing the factory heat shrink I found that both handles had the blue wire break in two different places, I assume this happened due to wear and tear. So if you have this issue, remove the heat shrink and double-check the wires! MB wanted 300$+ a piece for the handles, and as it turns out the entire handles would need to be replaced if it was the sensor itself. ANYWAY, I patched the broken wires, threw some heat shrink on and BOTH handles are back to full functionality.
I feel like I just defeated the last boss, MB Parts Department
It will be great to know. Perhaps the same procedure as in the W211, i.e. a Torx bolt (not surprise) just below the weather strip at the height of the handle? Make a few turns counter-clockwise and pull the handle, of course being careful with the wiring ?
If you took any pictures of the broken, and fixed wires? Many would appreciate it.
W166 MONEY SAVERS:
1 - Spark plugs w/o removing the intake manifold
2 - AC electronic control valve at the compressor using after-market parts (requires compressor replacement otherwise)
3 - AC compressor clutch using part from Toyota (requires compressor replacement otherwise)
4 - Keyless Go broken wire
Sorry I didn't take any pics of the fixed wiring, are you able to see the pics I posted of the broken wires?
Anyone with basic electrical skills can re-solder a broken wire and secure it with heat shrink/ tessa tape / electrical tape. A tip would be to ensure that you lengthen the harness when repairing it. AKA add a piece of wire to the harness, if you don't it turns out to be nearly impossible to reinstall the handle after plugging the harness in and then trying to fit the handle back into place.
I would also note that while there was corrosion on both my front and rear door handle connectors (pictured above), it was not the reason for the keyless go failure. I did hit them both with some electrical contact cleaner and dielectric grease upon reinstallation.
Removing the handle is the same as all Mercedes, use a T20 screwdriver to loosen the screw directly opposite of the handle on the inside of the door. This screw does not remove, so just unscrew until you can remove the rear cap of the door handle. Tons of videos on how to do this. Here is the one I used:
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It will be great to know. Perhaps the same procedure as in the W211, i.e. a Torx bolt (not surprise) just below the weather strip at the height of the handle? Make a few turns counter-clockwise and pull the handle, of course being careful with the wiring ?
