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Discussion Starter #1
I have a 2009 smart fortwo coupe that will not start. when I turn the key on there is no lights come on on the cluster, tern signals work, radio works, lights woek, wipers work,dome light works, but nothing comes on on the instrument cluster and I can not move the shift lever out of park. Also thebrake lights do not work. I have tested the battery and I get 12 volt, battery passes a load test. The 3 fuses in the battery compartment are good, all the fuses in the fuse box are good. I have removed the brake light switch and it tested good. When I turn the key on I hear what sounds like a relay click in I think the fuse box and one that clicks back in the engine compartment. When I tun the key to start I hear another relay click under the dash. I have tried reseting the cluster and still nothing. Can anyone help?
 

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Wow perked, this seems like an electrical issue for sure. You said you checked the fuses... OK, but there are numerous locations for fuses. The brake lights not working may have something in common. Besides fuses under the dash, I believe there are fuses in the glove box, and possibly some in the engine compartment.
You may also try checking all electrical connectors in the engine bay. I hope someone else can provide more info... sure would like to know the cause.
You may want to change your screen name to "parked" until you get this sorted out.
Don't give up, this is a talented group.
 

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Start with the easy stuff see if you have 12 volts before the switch activate the switch see if you have 12 volts after the switch and I’m sure there is a wire that goes to the shifter to activate the shift lock so see if your getting power there
 

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Hello Perked. The easiest thing is to start from the battery and work your way from there. Check the fuse marked F91 in the picture. If you have a multimeter or a 12 volt test light of some sort you can check to see if you have power on the wire AFTER the fuse. Set your multimeter on the 20 volt scale in order to read 12 volts on the car electrical system.Connect your meter or test light with the ground of the meter/light on the negative terminal at the battery. Then the positive wire to the battery plus lead and check for voltage. Then the wire right before the fuse and then after the fuse. A fully charged battery should be around 12.4 volts. Anything below 11 volts is for all intents and purposes dead. With the vehicle running and it charging you should get around 13.8 to 14.2 volts.

Maybe loosen up of the black ground battery cable and check it where it contacts the car (just above the F58 in the picture). The grounds are notorious for corroding and that could be your culprit. Next I would remove and clean the battery terminals and battery posts with sandpaper or a wire brush. DO this even if they don't appear dirty.
If that all checks out try putting jumper cables on it from another car or connect a battery charger and turn on the key and look for dash lights just to double check the condition of the battery. If jumper cables work or the battery charger causes you to have dash lights then you probably have a faulty battery or one that just needs recharged.

Worst case scenario is that you have a faulty computer on the car and it is called the SAM. It is the entire fuse box as a unit. It controls all the basic functions of the car on conjunction with the instrument cluster. Without the SAM working nothing on the car will do anything. It would take a long time to write all the reasons why you could have a dead Smart. But this should help you to begin troubleshooting. DCO


 

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Discussion Starter #7
The brake switch does not have any power going to it.
I spoke with a Benz mechanic on the phone and he seems to think the ignition switch is bad and not communicating with the computers but he can not say for sure without havinh the car.
I realy don;t want to haul the car 150 miles to be at the mercy of a dealer.
 

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I do not kow where the brake switch is on the smart... or how it is wired. But, did you check that with the brake pedal depressed, or would that even make a difference.
I guess if it is the ignition switch, you could get one from one of the many part outs, on this site and others. But since you have so many other components that do work, this really is enough to drive one to drink! It might be time to look for some wiring diagrams... have you checked Evilution?
 

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Discussion Starter #9
The brake switch is under the car in a compartment and is activated by the brake pedal arm. The switch itself is a double pole double throw type. There is 4 wires on this switch, 2 are suppose to be 12 volt going to the switch.
In the non braking position one set of contacts are connected and sends 12 volt out, when the brake pedal is depressed the switch disconnects that set of contacts and connects the other set of contacts to send 12 volt out via the other wire which I assume goes to the shifter release and probably activates the brake lights and who knows what else..
Since I do not have 12 volt getting to the switch the bad ignition switch idea makes since, as the ignition switch tells the SAM and the ECM what to do. I can get an ignition switch from a wrecked smart but it will not work with my car or key. I would still need to take the car to a dealer to have the ignition switch programed to the car and my key programed to the switch but I don;t think a programed key can be re-programed to a different car so I would need to buy a new switch. I can also get a switch with key from a wrecked smart but a dealer would still need to program the switch to my car. Before I did any of this I would want to make sure the switch is the problem. I have gone over every inch of wiring and every connector I can get to without taking the car completely apart. Nothing on evolution concernig this problem.
I was also told by a local mechanic that the key could have lost sync. with the switch.
Do any of you have a spare key for your smart that is just the blade with no fob, this type of key would be for unlocking the door and it will fit into the ignition but will not start the car.
 

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Just guessing, but if the ignition switch was bad you wouldn't get all the normal lights when you turned it to position 1. The indications you have are no instrument cluster and no power to the brake switch - what do they have in common?

You mentioned hearing a click from the rear - need to check and see if that is the clutch actuator. If it is, it's getting a signal to depress the clutch in preparation for starting.

Impossible to diagnose this online - if there's a local shop that does Mercedes work and has a STAR machine it would be worth having them check it out. :)
 

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Discussion Starter #11 (Edited)
When the ignition switch is activated the switch sends out data signals to all computers ( the instrument cluster is a computer as well ) on a few different data lines leading off of the switch which then tells the computers to power on.
In some cases, one or more of the data lines can fail in the switch or they may all fail.

If someone had a key that is just the blade and put it in the ignition and turned the ignition on to see if the instrumrnt cluster would light up or not.
 

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This probably will not help, but I got two keys with my car. I was told one was bad, and needed reprograming. I looked into that, and was about to send it off. But some where I read to try this.
Kind of similar to re learning the clutch actuator... I used the fob to lock, then unlock doors, foot on brake, inserted key to pos 1, then did the shifter thru all gears, then back to P, foot off brake, and key off.
Oddly enough, my key that would only open the doors before, became fully functional, it starts the car just fine.
Now, I do not remember if the instrument cluster illuminated or not prior to the key starting to work.
Also, have you tried to disconnect the battery for a while? Maybe leave it disconnected over night?
Just shooting from the hip, but you never can tell, and if it saves you from taking it to a dealer.....GR8!
Where are you located, someone out there has got to be able to lend a hand.
 

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I am pretty sure that the switch itself is a typical on-off switch that opens or closes a contact to the SAM to tell the SAM to turn on. Once it turns on, the immobilizer ring around the switch reads your chip in your key and if the codes match the Sam goes ahead and cranks the engine over. The split second it starts to turn over you can release the key and the SAM will continue to roll the starter until the engine starts. When you first insert your key into the switch and turn it right over to start, you will notice that there is a short delay before the engine cranks. That is because the CANBUS is initializing. The Sam does most of the work but when it comes to CANBUS and the storing of error codes, that all happens in the instrument cluster. It stores info on the state of the CANBUS. But the cluster receives it's power from the SAM. The SAM is the central power to fire up all the modules and the instrument cluster. I think I would drop down the SAM or unplug the connectors and completely remove it. Open it up and look for corrosion or cold solder joints. The SAM boards are multi-layer so they are interconnected with ribbon cables, so there is a lot to check. There is a large red cable on the top side of the SAM that powers it from the battery. Check that connection and also read the voltage there to see of the SAM is actually receiving power. There are several relays inside the SAM that controls various things but I would just almost bet your power problem is inside the SAM. I have a PDF of the procedure for removing the SAM if you need it. Just PM me your emai address if you need it. I have more info I could probably conjure up. I have a lot of stuff archived on my laptop. Lastly do you have 4 way flashers that will turn on and flash? They will operate with the key off. So that should tell you if you are getting something from the battery. If you have the factory lowline radio (non CD and mp3 jack in the glove box) try the radio. It will operate 15 minutes before shutting itself down when the key is not on. So does that work also? You can remove the instrument cluster by grabbing both sides of it and gently pulling it towards you. Check those connections. If you have the Tach and clock pods those 3 wires run to the instrument cluster too. But check the connections. I have the pinout diagrams I think in a Microsoft Word format if you would need that. Last of all to check for power I would raise the car up in the rear and crawl under the driver side and remove that little cover that covers up the starter's solenoid and check for voltage there. If there is voltage bridge the battery terminal wire on the starter to the smaller wire and see if that activates the starter. DCO
 

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Discussion Starter #14
Yes it is my understanding that the ignition switch turns the SAM unit on and off and the SAM unit feeds power to the other components.
I have had the SAM unit loose from the car to check the fuses on the back side but did not completely remove it. I see there is a good article over on evolution about the sam unit. I will remove the SAM unit and check all the plugs for corrosion and burnt pins. I have checked and there is 12 volts at the starter, I jumped the starter terminals and it did activate the starter.
I know the SAM is getting power because some things work like the wipers, blower motor, headlights, tun signals. I will check the instrument cluster fuse which I believe is fuse 12 to see if there is 12 volt there.
 

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I saw a You Tube video of a young fella that had a similar electrical issue and he fixed it by touching up the solder joints on the SAM unit.

His channel is Aging Wheels. I'm not allowed to post links yet.

Search for video, "I fixed my Smart for Free".
 

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Discussion Starter #16
I removed the SAM from the car and did not see any burnt or corroded pins or plugs. I took the SAM apart and could not find any cold solder joins or corrosion anywhere. I did see where here had been water in the SAM at one time so maybe it shorted something out.
I have been told by MB I can not take a SAM unit from a different smart car and put in mine, it won't work. Has anyone tried this?
 

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I am not sure but as far as I am aware the only parts of the CANBUS system that records the VIN inside is the SAM, the instrument cluster and the Air Bag module. I don't know if this is correct as I haven't found the info to support or disagree one way or the other. I have replaced my air bag module on mine because I damaged the originally as I was attempting to fix a faulty seat belt error that I could not get resolved. I transplanted another air bag module from another Fortwo but I get the VIN number does not match error and still have the original seat belt error code. So it seems MB has thought out the whole scenario of replacing individual modules yourself with having access to a STAR computer to sew it all back together. DCO
 
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