Alex

Sam Woes, And How To Cure Them.

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Posted (edited) · Report post

So my passenger side headlight went out, no biggie, I've got the bulb change down to 2-3 minutes.But the bulb looked fine! Measured fine as well, so I checked the SAM as that's been known to have connection problems (and that's putting it lightly!).Yup, connector melted, pins burnt. I need to dig out my radio code, pull the SAM and do some surgery. Solder wires to the base of the burnt pins and run them outside to individual connections. Still better than what MB would do, a new SAM, new harness, programming, probably $1500 by the time they are done.My prophylactic cleaning and NoAloxing 100K km ago may have helped, but didn't make it immortal.At least I can do the work...Pictures and a description to follow, that's why this is in the How-to forum.Very late edit: Another very common problem is pin 10 on 11-3, which is for the low pressure fuel pump. Symptoms are usually an intermittent no start condition, when the engine cranks normally but won't start. Get worse over time, early on wiggling the connector will restore connection but it just gets worse.Even later edit: This whole thread is true and useful, but take special note of the new recommended permanent repair at the end.

Edited by Alex
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Posted (edited) · Report post

Full success to report.

Many SAM units have been replaced due to the connections failing. Replacement repair harnesses are available, but once the connection has failed the pin on the SAM is usually heavily damaged and will not make for a lasting repair. It is easy to repair by bypassing the failed connection, with only basic soldering skills and some common supplies.

Refer to this Evilution page for wiring diagrams and great photos. Note that the connections list is for the petrol 700cc UK model, there are a few minor differences with the Canadian CDI. Mostly identical, though. Go with what you see, not what the list says.

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The damage. Two connections melted and burnt at the center of the connector, they are pins 6 & 7 of connector N11-3, which are the low beams. Also pin 11, brake light switch, looked suspicious so I did that one as well. Much later I discovered that I should have done pin 10 at the same time.

Tools and supplies needed: 10mm socket, pliars, a T-10 torx screwdriver (must have longish shaft, the screw is down a hole a ways), soldering tool and supplies, 14 or 16 ga wire, preferably in as many colours as you have pins to repair, crimp-on connection terminals, crimping tool, drill and bits, good write-on sticky labels. Radio code, as the radio will go into safe mode.

Procedure: Disconnect the negative of the battery. This is a good opportunity to remove the battery, clean and top it up, clean the battery well and apply some rust preventive inside there. If it is really nasty a good cleaning, drying then a spray of undercoating compound works very well. Available in spray cans from any automotive supplier, even Crappy Tire.

Remove the SAM, making note and taking photos of where the various plugs go. They won't interchange, but some are very similar and it can be hard to tell if it doesn't fit or is just not lined up right. Inspect each connector for signs of heat damage, darkened pins and melted plastic. Make note of the connector number, pin position and wire colours. The most common problems are all on 11-3, pins 6,7 and 10. L & R low beams and the fuel pump. May as well do these three even if they look OK, enough cars have had problems that yours is just a question of when.

Take the SAM to a bench, opening it up as per Evilutions excellent description. Note that you have to remove the four large fuses on the connector side, all the small ones on the back can stay in. Write down the amperage and positions of the four.

Yes, you bend the board to unfold it, being sure you've found all the plastic hooks that clip it in. Be careful and gentle, don't bend it more than you need to. Before unfolding it think about how your new wires bypassing the pins will route nicely in the folded position. Try hard not to have to fold and unfold it repeatedly, try to get it right the first time.

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The opened up SAM. You can solder your wire to the base of the pin, or follow the track to the other end and use that if the wire will route better. I used the other end for the headlights (pins 6 & 7), it worked better for me. The fuel pump (pin 10) wanted to come up a new hole drilled in the centre of the divider plate.

Double check you have the correct point, solder the wires marking down the wire colour and pin position, or some way of identifying which is which. Carefully fold the board back up, watching that your new wires lay into a good position and especially won't get pierced by one of the solder points! An empty plastic pop bottle or yoghurt tub may be handy to cut protective strips from. A hole drilled in the plastic separator plate may assist wire routing. If you have to route the wire around the separator a notch must be trimmed in the edge, it looks okay when open but it's a tight fit when the board is folded down. Drill holes in the case to pass the wires through and reassemble the SAM.

Write down the identification of the new wire(s) on a label and affix it to the case.

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Done!

Re-install the SAM, crimp your choice of insulated dis-connect terminal to the wires, cut the harness wire and add the mating crimp terminal to that. If the heat damage has moved up the wire cut it off, adding a new section if needed. Once a wire has discoloured from heat you'll never get a good connection, it must be clean shiny copper. If you have a variety of terminal styles and sizes you can make the new connections non-interchangeable. Wire marker labels are nice to have.

Connect the battery, check the function, enter the radio code and go out for a really nice dinner with a fraction of the money you just saved.

Edited by Alex

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I bought a new connector from the dealership and I've spliced it on to the old wires. My old connector was pretty bad. Before I did this, one of my headlights did not work, but now it works fine. I did not remove the whole SAM, I just spliced on the new connector. However, the bigger problem now is that the car will not start. About a year ago, the dealership did some work on this same connector, specifically socket #10 on the connector and pin #10 on the SAM. See the attached picture. They put some kind of extension on pin #10. The symptom at the time was that the car would not start unless I wiggled the connector. So I was at least able start it and drive it to the dealership so they could "fix" it. But now I can not start it at all so I can't even drive it in. Is there some test I can do on the SAM and pin #10 to see if this is, in fact, the problem? I'm ok with taking out the SAM, but how do I confirm that this pin is the problem and then what would I do to fix it? Would I bi-pass the pin and solder the wire directly to the board? I'd rather not attempt this unless I know for sure it will work. It took me about 4-5 hours just to swap the connector…Thanks

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Posted (edited) · Report post

Connector 11-3, pin 10 is the low pressure fuel pump. (In the fuel tank, feeds the high pressure pump which is not good at sucking. Really good at making 50 000 PSI or so on the high pressure side, but it won't suck.) It should have 12 volts all the time the key is on. Without changing both parts of a connection, both the pin and the plug, a reliable repair is unlikely.HTH, Alex.

Edited by Alex

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Thanks for the info. So I checked and there is 0 Volts (wrt ground) at Pin 10 with the key on. How would I replace this pin or do you have any other suggestion for me at this time? Thanks, DZ

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Posted (edited) · Report post

My SAM repair above! By far the best way.

In your particular case, because the power you need is constant on with the key, you can also use one of the switched accessory fuse connections along the side of the SAM. Be sure you get the switched connection, not the unswitched, otherwise you'll drain the battery after it sits for a day.

See THIS Evilution page for details. Note you couldn't do this with many SAM functions, only a few things that are on all the time the key is on.

(Edit)

My apologies, that is WRONG! The low pressure pump is shut off by the SAM under certain circumstances, such as during engine braking above some threshold RPM for some particular length of time, and supplying constant power will cause a nasty limp mode and code PO202. You must use the correct circuit out of the SAM, attaching your new bypass wire inside the SAM.

It doesn't make sense to me, appears to be setting up the possibility of pump damage due to cavitation or fuel overheating, but that is the way it has been programmed.

Edited by Alex

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Mine wasn't too burnt, just took a paper clip and cleared the contacts and the lights worked. Still would recommend buying a new connector and splicing the wire.

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Your headlight connections (6 & 7 from the left in above photo) look pretty bad as well. When a connector goes bad like that it ruins the surface finish of the pin as well, and a lasting repair is unlikely by just changing the connector end. Cleaning the pin up with a tiny fine file helps.

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Thanks for the info. So I checked and there is 0 Volts (wrt ground) at Pin 10 with the key on. How would I replace this pin or do you have any other suggestion for me at this time? Thanks, DZ

My SAM repair above! By far the best way. In your particular case, because the power you need is constant on with the key, you can also use one of the switched accessory fuse connections along the side of the SAM. Be sure you get the switched connection, not the unswitched, otherwise you'll drain the battery after it sits for a day.See THIS Evilution page for details. Note you couldn't do this with many SAM functions, only a few things that are on all the time the key is on.

I've done this & my intermittent start problem has stopped!

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An inadvertent serious error appeared in post #7 above. It has been corrected.

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Thanks very much for posting this. We bought a new (to us) 2006 Fortwo Passion CDI on Monday and on Tuesday it refused to start. We sent it to a local repair shop who specialise in german cars since the nearest dealership is 100km away. They did some troubleshooting and said it was the SAM box. I mentioned that many people experiencing this difficulty had issues with bad connectors on pin 10 at 11-3 so he pulled the SAM for inspection and lo and behold, the knowledge I'd garnered over the last few days reading threads here proved very useful. So here I sit with a SAM box in my lap trying to remember where my torx bits are. I'm very glad this thread in particular was available. They quoted 1050 or so for a new SAM but were willing to let me have a go at the rewire. Said they couldn't do that themselves due to potential liability problems. I'll post my results probably Monday.Thanks,Mike

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Does anyone know what amperage 11-3 pin 10 is (fuel pump). I'm trying to figure out what gauge wire to use (and also finding my soldering skills pretty inadequate)

Edit: I found a guide for DC wiring here: http://www.windsun.com/Hardware/Wire_Table.htm and also found info out there that seemed to indicate that low pressure fuel pumps are generally 5amp so I went with 14 gauge stranded wire as opposed to the 12 gauge solid core I started with. My soldering woes I fixed by firstly buying a new soldering iron and secondly reading the instructions. The new iron has a very fine point tip on it and the instructions said to pre-tin both sides before soldering (the things you forget when you only do something once every 30 years or so.

Anyway, I have my SAM unit back together and will be having it put back in the car hopefully tomorrow.

Edited by miker

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We got the SAM back in the car and I was all ready for everything to be great, but there's one hitch: the low pressure fuel pump DOES come on, but now it WON'T turn off even when the key is turned off. Have to disconnect the battery to get it off. I'm going to take this opportunity to get it back from the shop and then remove the SAM again myself and check the internals out and see of there's some kind of short somewhere. Very puzzling.ps: could someone let me know if they're reading this at all or am I just talking to myself?

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I'm reading it but can't help....

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There is an unused pin 12 on N11-3. Did you accidentally hook up the fuel pump to the source for pin 11 instead of the proper 10?Pin 11 is unswitched power for the brake lights.

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[Thanks for the responses, MikeT and Alex.I'm pretty darned sure I got pin 10, having counted 10 pins from one side and three pins from the other. I also did continuity checks with an ohm meter to make sure I had a connection between just pin 10 and not any adjacent pins. That said, possibly a piece of loose solder has shorted the connections between 10 and 11. Does unswitched mean it runs straight off the battery and doesn't require the key in the car? If so, that would have to be the problem.

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[Thanks, Canman. That's quite illuminating and is another thing for me to check. I had the SAM removed at a local shop and they've reinstalled it. My plan is to drive it home tonight and then fix everything myself once back in my carport. I doubt the 'technician' (what's wrong with the word 'mechanic'?) took pictures before unplugging the fuses, so I'll have to figure out where they go myself somehow.

Edited by smart142

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Miker,I have a photo on my iPad, it's too big to attach here.P.M. me your email address and I will send it to you.CanmanEdit, I guess it worked after all, all 3 pics are the same.

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Edited by CANMAN

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I doubt the 'technician' (what's wrong with the word 'mechanic'?) ...

"Mechanics" know what they are doing and why, try to figure out what caused a failure, can repair parts when practical, understand what parts do and how they work, and much more. A dying breed."Technicians" plug the car into a computer then follow the procedure that the computers give them to swap out the assemblies that the computer thinks is the problem.

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"Mechanics" know what they are doing and why, try to figure out what caused a failure, can repair parts when practical, understand what parts do and how they work, and much more. A dying breed."Technicians" plug the car into a computer then follow the procedure that the computers give them to swap out the assemblies that the computer thinks is the problem.

And then there are hacks like me who blunder along and hope to learn something each time out =)
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I've attached a pic of what my fuses are looking like. I moved the purplish fuse holder to a switched socket but no change in behaviour. In the process of pulling the SAM so I can open it up and check the internals to see if there's a rogue blob of solder or some other malevolent being in need of removal. My Hallowe'en SAM exorcism I suppose. Sorry for the blurry picture, not much room to play with the camera under there and the carport it's in is tight quarters to begin with. I'm almost tempted to pull the seat out.update: I have the SAM apart and found that the wire I ran out through it got pinched on top of several pins on the PCB. At least two of them pierced the wire so I'm thinking one of them must be on an unswitched circuit. Redoing the wiring/solder job now. Oh how I wish old school electronics shops still existed around here so I could get someone competent to do this part :lol:

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Edited by miker

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Hopefully this is nearly the last time I need to post in this thread. I put a new wire in the SAM, carefully bent it around any pins on the pcb and out the hole I'd drilled in the SAM case. Then I reinstalled it back in the car and hooked up the battery. Blissful silence ensued. Encouraged, I proceeded to start the little car and it went almost flawlessly. Motor ran, fuel flowed and everything was perfect. Until I looked at the dash and saw my car now had -2km on the odometer and twin wrenches flashing (which I assume and will now look up in the manual to see if it means 'needs servicing'). I hope I can get the odo back reading properly, but if that's the only permanent problem, so be it. Tomorrow I'll finish up and get everything tucked away properly.

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