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Discussion Starter #1 (Edited)
The interior lock and unlock buttons on my ED have suddenly stopped working. The buttons themselves still work because they can still be used to enable/disable the lock-doors-when-moving function.

I tried a "reset" of the SAM by disconnecting the battery but that didn't work.


Ideas?

And I discovered another aspect of the locks. I decided to test the driver-side keyhole which I had presumed was for manual mechanical locking and unlocking. I discovered that it only works for unlocking, and is not mechanical at all, but is apparently a switch which actuates the lock/unlock relay. The importance of this of course is that if the battery ever goes dead while the car is locked, there is no way to enter the car except via old-fashioned "break in" methods. A flat but rigid bar slipped in through the top of the window to work the door handle being the easiest method that I can see. I'm tempted to make such a bar out of aluminum stock and keep it under the front "hood".


The owners manual has nothing on this manual keyhole BTW.
 

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The keyhole lock activates the electric lock solenoid and you should only try to rotate it one direction and that's the direction that unlocks the door. The lock cylinder is connected to the switch by a cable and turning the lock cylinder the opposite way causes it to bind the cable and over time the strands will fray and break and the cable will break in two. I had to replace the driver latch because the former owner of my fortwo always unlocked with the key because he only had one key. Well I got it just in time to have to replace the latch because the cable assembly to the lock isn't replaceable. As to the battery dead syndrome, I connected a 12 gauge wire to both positive and negative battery terminals and ran them through the firewall plug above the brake pedal and under the service flap. I put a wire nut on each. That way if the battery dies you can take off the service flap and connect a battery charger to energize the system enough to unlock the doors. DCO
 

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The keyhole lock activates the electric lock solenoid and you should only try to rotate it one direction and that's the direction that unlocks the door. The lock cylinder is connected to the switch by a cable and turning the lock cylinder the opposite way causes it to bind the cable and over time the strands will fray and break and the cable will break in two. I had to replace the driver latch because the former owner of my fortwo always unlocked with the key because he only had one key. Well I got it just in time to have to replace the latch because the cable assembly to the lock isn't replaceable. As to the battery dead syndrome, I connected a 12 gauge wire to both positive and negative battery terminals and ran them through the firewall plug above the brake pedal and under the service flap. I put a wire nut on each. That way if the battery dies you can take off the service flap and connect a battery charger to energize the system enough to unlock the doors. DCO
I did the same exact thing.
I can hook a battery maintainer or plug in a small set of jumper cables I have stored under the service hood.

JL
 

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Discussion Starter #4
Yup - I'll do the same thing so that there is full-time charging access. There may also be full-time energized wires under the service flap (I didn't know that was the name for it) that charging wires can be spliced onto.

And another idea for the Smart ED mount a small SLA backup battery under the service flap - in addition to operating the locks, it is probably all that is needed to turn the electronics on so the car can be "started" (i.e. no starter to crank in an electric car). The DC-DC converter in the traction pack will then charge the 12V battery the rest of the way.

The idea that they would put a lock cylinder in the car and not make it mechanical is still absolutely idiotic.
 

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I’d make sure there’s a fuse or fusible link near the battery on any +12V wire being added to the car.

Even the low voltage battery can heat up a wire pretty badly without a fuse.
 

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Discussion Starter #6
Another trouble I'm having with locking. I often intentionally leave the car unlocked, either where it gets parked behind my house or at work in a secure facility. But recently, coincident with those lock/unlock switches failing, It is now sometimes, randomly, locking itself. Yesterday, as part of a test, it even locked itself with the key in the keyswitch. Of course for this test, I left a window cracked down enough to reach in and pull the door handle, so I could get in.
 

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My standard rule is if I am not in the car, the key is in my pocket Have had that happen over the years. luckily I was near where the spare key was.
 

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Discussion Starter #8
Maybe I _want_ to leave the key in the car in some situations. The car is supposed to serve my wishes, not me the car's "wishes".

Also, the number one rule of human factor design and safety is to not make a machine that required a human to always remember to perform a specific action to prevent a incident or accident. What they have created is a situation that a lockout is even more likely than the old days of purely mechanical locking.

I sure long for the days of plain old keys and mechanical locks.
 

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Another trouble I'm having with locking. I often intentionally leave the car unlocked, either where it gets parked behind my house or at work in a secure facility. But recently, coincident with those lock/unlock switches failing, It is now sometimes, randomly, locking itself. Yesterday, as part of a test, it even locked itself with the key in the keyswitch. Of course for this test, I left a window cracked down enough to reach in and pull the door handle, so I could get in.

I believe the button bank in the 451 uses elastomeric buttons coated with a conductive material which, when the button is pressed, shorts across two contacts on a pcb. This coating can flake off or fail, as well a buildup of a film on the pcb can become conductive when humid.

I would expect that unplugging the button bank would prevent the random locking. I don't know if it might set an error code.

If unplugging the button bar stops the random locking, try disassembling it and cleaning the contacts with some alcohol.

~toaster
 

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Maybe I _want_ to leave the key in the car in some situations. The car is supposed to serve my wishes, not me the car's "wishes".

Also, the number one rule of human factor design and safety is to not make a machine that required a human to always remember to perform a specific action to prevent a incident or accident. What they have created is a situation that a lockout is even more likely than the old days of purely mechanical locking.

I sure long for the days of plain old keys and mechanical locks.
The smart is what it is. The 451 is not going to be updated as it is out of production. It's common knowledge that if you use the key fob to unlock the door and then don't open the door the car will relock itself. If the door has been opened, no relocking should occur. Can't imagine a scenario where the car would randomly lock itself, but smart has always warned against leaving the keys in the car..... YMMV. :)
 

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Didn’t realize this was a problem .....

I thought I was one of the only people in the world that locked myself out of my car and or house.

It has to be over twenty years ago. I locked myself out of my car. I told myself, never again. I always carried two sets of keys. In the winter, easier because I would always put a two extras in the coat.

Summer was harder but I never went out without two car and house keys.

The Smart was the first car I ever owned with a key fob. Thick, so I had to carry an inside the belt wallet but I won’t leave the house without the second Smart key.

The house was solved by getting electronic locks. The type not connected to the internet. I haven’t been locked out of any car I’ve ever owned since that last time.

A pain but for me, worth it. While I’m at it. My 2016 gas use to lock the whole car down when it reached 15 miles an hour. It also locked itself if left unattended and not locked for the night. The 2018 ED does neither.
 

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Discussion Starter #13
Today, the locking went haywire - auto-locking, then the locking relays clicking repeated random times while the car was being driven. The unlock button suddenly would start working again during this period.

Then it went back to nothing working again.

I still think the problem is in the SAM or a connector.
 

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Discussion Starter #15
Isn't the whole purpose of this forum - or any other kind of forum where prodicts are discussed, for people to offer design criticism, discuss design flaws and poor design, and discuss troubleshooting and repair of problems - including work-arounds for lousy design?

And are you suggesting I'm making up the problem I'm describing?

And the Smart is a car - something we buy with a lot of hard-earned money and which we expect years of reliable service - not a deprecated piece of planned-obsolescent software.

I'm pretty sure the 453 has exactly the same locking syatem.

The soonest service appointment I could get for this car was September 5 - another problem with Smarts - the lousy dealer service. Based on this similar sounding problem in the link below, they might be replacing the SAM and replacing or reprogramming the keys. Thank goodness it is still under warranty.

https://www.computerweekly.com/blog/CW-Developer-Network/How-to-reboot-a-Smart-Car-software-system
 

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Discussion Starter #16
This morning I went out to the car and the car was locking itself (i.e. lock relays in the doors and gas cap actuating) repeatedly at 1 to 15 second intervals. Wondering if it had been doing this all night, I turned the key switch on to charge the battery and left a door ajar. It stopped for now. I may have to disconnect the battery...
 

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Yinzer are you sure that possibly you could have a faulty button on your key FOB? Or do you have an extra key on the house in a drawer that might have gotten something knocked over on it that it is pushing the lock button? Sounds crazy but could be a possibility. Could be the button bank? Do all the buttons feel the same when you push them? I've carried my key FOB in my pocket and bent over to pick up something and set off the panic button and the horn and lights went crazy. It could be a bad relay in the SAM. I do not know if the wireless module that listens for the signal from the FOB is a separate unit or built into the SAM. Does it do it's random unlocking everywhere? Or just like in your driveway or at work? Maybe a stray radio signal of some sort is triggering it. Will the system lock doing this?....star the car, while it is running, push the lock button on the button bank on the dash. The locked LED on the button bank should start flashing. Shut off the vehicle, remove the key, exit the vehicle and close the door. Did it lock using this method? DCO
 

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Discussion Starter #18 (Edited)
No, a bad key transmitter would not have anything to do with lock/unlock commands from the dash buttons not working.

I just popped the button panel and was surprised to find that instead of the whole assembly coming out, only the plate with the buttons and a silicone tactile-switch membrane (like is used in calculator or TV remote keys) come out. The underlying PC board with the switch contacts and LED indicators can then be removed via a pair of screws behind the pop-off plate. I cleaned the membrane and put it back on. Still no go.

I lowered the SAM unit and checked the connectors. Still no go.

But some internet research indicates that this locking failure is a typical indication of a SAM failure - usually due to too much moisture getting into it. It's location just above the drivers left foot means that it can get exposed to water from wet, or salty and slushy boots when used in a wet and cold climate. And of course, its been a very wet and humid summer.

Replacing the SAM is not a DIY job - it needs to be assigned particular codes (called "SCN's") for the particular car and the keys used with it. And used ones from a junkyard supposedly need to be "virginized" to be SCN'ed for use in another car! Only the dwindling number of authorized Smart service centers have the equipment to do any of this.

My Smart is on warranty for another 8 months. After that, should a SAM fail again, it is a very expensive repair.
 

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Discussion Starter #19 (Edited)
Update...

The problem kept getting worse until during its fits of locking it was hard to unlock at all - it would quickly re-lock the door before you could pull the on the handle and open the door. It was like some kind of gag setup on the vintage TV show "Candid Camera".

The MB dealer replaced the SAM - costs $1018 - not including the electronic configuration of the unit that only an MB dealer can do. It's still under warranty, thank goodness.
 

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I am happy for you.

As Smart owners we are aware of glitches to every single car they’ve made.

It might be something tiny, mine is, the turn signals are not up to spec. Instead of a thump, one cancels with a crack. I’ve gotten use to it. It doesn’t bother me at all.

MB Escalated called it, OPERATIONAL. Now, that’s a different issue.

When I turned in my perfect 2016 gas with 3100 miles on it, Autovin put down 350$ for a glitchy display under warranty which they wanted me to pay for.

The car brought nearly retail at auction from a dealer that treated me like Mr. Daimler, dressed like I usually do, out of a freak snow, rain, ice and fog trip.

One salesman told me he would take off the plates. I said, no, please, I’m filthy, there were accidents all over on the way up.

He said no. I could not give you your plates. I have to clean them first. What. Shocked I took my screwdriver out and offered it to him. He said, we have them and chuckled nicely.

It’s the MB dealer in Syracuse, NY. It was the best treatment I had ever received. In my life it was the only time I didn’t have to take off my plates.

He returned them with a smile, clean and dry. I called as high up the ladder I could get and thanked them all for the treatment I received.

I am happy MB is honoring the warranty. That is pretty stiff. Be careful or the either or on warranties.

I don’t know if it is standard but with 3100 miles, I was responsible to get it serviced before the year was up. I know everyone knows that, it’s just for the next time I see my own post, to remind me.
 
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