EmilysDad
Senior Member
Well done on the repair!
How did you know which chip you were swapping?
How did you know which chip you were swapping?
OK - Problem has now been solved - I bought a 2nd hand ECU with matching part number, software version and Q number (not sure if the last 2 specifics are important or not) - The ECU does not need to come from the exact same model of car I believe - just match the numbers.
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I opened up both old and new ECU's and located the chip which needs removal - (shown circled) and marked the old board with sharpie - I also added a very small dot of nail varnish to the top edge of the chip I wanted to remove with a pin - This helps to keep track of which is old chip and which is new chip (in case of sudden gust of wind or something - it also helps when fixing the chip onto the new circuit board to ensure it is the right way up!)
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You need to remove the circuit boards from the metal housing - Some mild heat may be necessary to soften the sealant holding the back plate onto the circuit board.
Next - I cut out some kitchen foil peices with a chip sized hole in them to act as a heat shield - I used 3 layers.
Then, I heated both boards in the oven to 100 degrees c just to help prevent shocking the boards when I used the heat gun - I put both in with the oven cold, and let it get to temperature - then removed.
On a flat surface I then added the heat shields and used a hot air gun set at 365 degrees and wafted this over the chip pins on the "new" ECU VIN chip, going round the chip for about 10 seconds while holding the chip with tweezers - once free of the board, discard this chip.
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Returning to the cars original board, I removed the same chip and kept it safe.
On the "new" circuit board, I cleaned the 8 tracks where the chip pins go with a quick run over each one with a soldering iron, then carefully placed the chip I had been keeping safe onto the board, and held in position with tweezers while I fixed each chip pin to the board with a soldering iron.
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Allow to cool, reassemble into the metal housing, and refit (with the car battery disconnected) - and as if by magic I have a car which starts again for the princely sum of £33 in parts - and not some horrendous invoice from a specialist!
Is your SAM in the same enclosure, as mine is?
I've seen SAM's go down due to ingress, well doing strange things with lights and horn. But on oldish MB's they're just plug and play when a same SAM is sourced.
Well done on the repair!
How did you know which chip you were swapping?
In the Vito / Viano there is only the front SAM. I'm aware of some having a rear SAM.
So in my case Yes the front SAM controls rear lights.
Perhaps a little late for you but I carry a spare SAM (the original that went u/s) that has a known fault. If this one plays (assuming with a different fault) up I can swap out and prove / disprove.
I saw it on a video on Youtube - but I only took a screen shot of the video and didn't save the link.. if I find it I will post.
Funny you should say that - Since doing this job, I have noticed one (only O/S) reversing lamp has decided to come on when the car is switched off - but does the front right (O/S) SAM have any control over the rear lights? I've just taken the front right SAM out and it appears to be perfect inside - no corrosion on the metal tracks, or indication of water ingress inside the circuit board..
Does any one have any solid information about which SAM has control over the reversing lights?
Well l'm vastly impressed with the op's knowledge and skills here. Makes me very proud to be a member of this excellent forum. Well done on keeping an old Merc on the road at minimal cost.