Some Information Which May Help Others Repair Water Damage On Their Sam Circuit Board

[smartdriver 49]

There have been threads on how to repair a SAM module affected by external water damage which affects the connectors.

On my SAM, the damage was internal with corrosion eating away a number of traces.

My main symptoms were no turn signals and a right turn signal which came on when the emergency brake was applied and no left air-conditioning light. The corrosion was from water ingress on connectors N11-8 and N11-9. My problems might have been compounded by overcharging on numerous occasions a sick battery which put sulfuric acid fumes in the car.

When I took my SAM apart there was corrosion in two places on the board some of which I was able to fix with jumpers.

This fixed the air-conditioning but didn't fix the turn signals.

The worst damage was a corroded 74HC151 multiplex chip.

This chip has 8 inputs and receives the signals from switches in the car (turn signals, wipers, emergency brake etc.)

The computer scans the inputs one at a time and tells a relay whether to turn on or off.

I replaced the chip. Still no turn signals.

The fact that two things were happening at the same time for some switches indicated to me that some of the plated through holes on the circuit board had corroded which disconnected the input to the chip.

Because this is a CMOS chip, an unconnected input could make the output go either way. It is for this reason that every input on the connectors is terminated with a resistor and capacitor.

From information from EVILUTION and FQ101.CO.UK, I was able to determine which inputs were involved in my problems and was able to test with an Ohmmeter the input connections to the chips. These connections are shown in yellow and using an Ohmmeter should measure zero Ohms from end to end of each of the yellow lines.

http://www.fq101.co.uk/images/450/electrical/SAM.pdf

http://www.fq101.co.uk/how-to-guides/fortw...am-removal.html

http://www.fq101.co.uk/how-to-guides/fortw...sam-wiring.html

http://www.evilution.co.uk/index.php?id=721

On the picture of the topside of the board I have put yellow squares around the input lines and orange squares around the address lines.

The input pins on the chips themselves may then be tested for continuity to ensure that the plated through holes are OK.

All of mine were OK.

There is another way that two items could be turned on at the same time.

If the 3 address lines (Pins 9,10 and 11) were not properly connected, this also could cause a problem.

Unfortunately the address lines go through plated through holes under the chips, so I had to remove it again.

Sure enough, the plated through holes for the address lines which are under the chips were corroded and I had no idea where to connect them, but I got lucky. One of the lines was still connected and making contact with the address line of the other chip. This meant that I could connect the address lines of the two chips together above the board with jumpers.

In the pictures below taken from the Evilution site I have shown in yellow many of the input connections. There should be continuity from end to end of each yellow line. This will confirm that the plated through hole along this path is OK.

The address pins I have shown in orange. There are three and they are connected together pin to pin on each of the two chips.

Edited August 21, 2013 by smartdriver

[2seatragtop 3]

Hi Smartdriver,I have been trying to resolve a similar problem but I think it is less severe than yours.2 years ago I found water in the SAM and cleaned it out and added conformal coating and drain holes. You may have seen the thread on this site.This worked fine until a couple of months ago when my left turn signal quit and at the same time the cabrio roof only partially opens. It sometimes went away and then reoccured. The last time it was working I then went for a carwash as a diagnosis and sure enough it came back almost imediately. I traced a common area to the SAM unit N11-9 using evilution and fq101 site. I have opened and looked at the SAM without infolding the board but was unable to find any evidence of corrosion but I think after your story I need to open her up and look closer. I had been hoping it would be a bad common ground but I am starting to accept the inevitable.Thanks for posting and I'll let you know what I find when i finally get around to trying to open her up.2seat

[smartme 6]

That's real nice of you to post such detailed info Smartdriver, thanks a lot for that

Edited August 17, 2013 by smartme

[MikeT 744]

Excellent work!

[smartme 6]

Smartdriver, what year and how many miles on your car? Mine is 05 with 115k and I was wondering when corrosion symptoms may start to show up on mine.

[stickman007 309]

Great job!

[smartdriver 49]

Thanks for all the kudos, but in this case necessity was the mother of invention.I was reluctant to part with $1500.

Smartdriver, what year and how many miles on your car? Mine is 05 with 115k and I was wondering when corrosion symptoms may start to show up on mine.

My car is a 2005 Cabriolet with 44,000 kM. It was manufactured in June 2004.My car has always been parked outside.There was little external evidence of water getting into the SAM module through the wiring harness and connectors on N11-8 and N11-9 although that is the likely entrance point.There is also the possibility of condensation from the cold of the air conditioning unit.As I had mentioned my severe problems might have been compounded over time by repeatedly charging a sick battery with an external charger and sulfuric acid fumes being released in the car.This is a very nasty problem and as time goes on I think it likely that more and more older smartcars are going to succumb. Edited August 17, 2013 by smartdriver

[smartme 6]

Doesn't look good for me then either as I was repeatedly charging my old battery until I good not getthe motor to turn over anymore and then got a new one. Another thing I need to doin Winter.

[smartdriver 49]

This worked fine until a couple of months ago when my left turn signal quit and at the same time the cabrio roof only partially opens.

I've been thinking about your problem.It seems likely to me that one of your address lines which go through feed through holes under the 74HC151 chip is intermittently open likely due to corrosion.You can test this by measuring continuity on pins 9,10,11 between each chip.The easiest solution would be to connect them with jumpers on top of the chips.Each chip is sequentially looking at 8 different switches.If one of the address lines is missing, the computer for example will be looking at the roof switch and acknowledge that it's the roof switch and then because of the missing address line when it gets to the left turn signal time slot will do whatever the roof switch is telling it to do.There are multiple other possibilities but for a first try I would add jumpers between the chips on the address lines. Edited August 18, 2013 by smartdriver

[Alex 21]

Nicely done! smartdriver should collect old SAMs, fix 'em and sell 'em!You still need to program them though, I think. They're not plug&play. Can they be reprogrammed for a new car? There was some talk, but I don't recall the details.

[MikeT 744]

I wonder if my old one could be repaired and re-installed in my car - whether it can or not, it's in a sealed plastic bag in my garage now. It has/had all the TAN codes in it.....is coded to my VIN....only the km readout would probably screw up. Or am I dreaming?

[smartdriver 49]

it's in a sealed plastic bag in my garage now.

Have you taken it apart and examined the board?It would be interesting to see where the damage was and how it correlates to your symptoms.http://www.evilution.co.uk/index.php?id=721The problem with trying to fix them is that at the present time I have incomplete information on where all the plated through holes go.It's a multilayer board and unless I take it to my dentist for an X-ray and have the schematic, some boards are likely to be non-repairable.The one encouraging thing is that the damage seems to be occurring in one spot with some common symptoms.Unless the damage is obvious, however, any initial repair is likely to involve some trial and error. Edited August 18, 2013 by smartdriver

[smartdriver 49]

This worked fine until a couple of months ago when my left turn signal quit and at the same time the cabrio roof only partially opens. It sometimes went away and then reoccured.

Just an update which may help fix this issue.After repairing my SAM module and happily driving around for 3 days, last night I went out to start the car and I encountered some new symptoms.Parking brake light onCabrio roof opening a few inches and then closingLeft turn signal onNo air-conditioningI couldn't believe it. I was certain that the SAM was OK.I remembered after removing the SAM 4 times that the black connector N11-8 had green copper oxide deposits on its face. Not a good sign even though the pins on the shell which they plug into looked OK.For this reason, after my problems last night, I sprayed the black connector N11-8 and the white connector N11-9 with a silicone oil like WD40.This morning when I started the car, everything was OK!It looks possible that oxidation on these 2 connectors were causing these symptoms and spraying them improved the situation.I would recommend before taking your SAM apart to look at these 2 connectors.One event reinforced my reason for spraying them.After first repairing my SAM, the right turn signal lights were flashing very quickly.The higher resistance of a burned out bulb turns the remaining bulbs on and off more quickly and is designed to tell you that a bulb has burned out. After about 30 seconds the right turn signal slowly returned to its normal flashing rate and it appears that this was due to oxidation on one of the pins on connector N11-9.Your original post about your roof problem was a factor motivating me to have a look inside my SAM module. I hope you can solve your problem by just spraying the two connectors with some type of lubricant-cleaner. Edited August 18, 2013 by smartdriver

[MikeT 744]

I may take mine apart someday, but for now I want to forget this whole episode.

[smartdriver 49]

I may take mine apart someday, but for now I want to forget this whole episode.

Me too!

[Alex 21]

Mike's is very repairable. The plug fails, pins and plug fry. The heat can conduct a little ways into the board, but it's all robust output stuff there. Easy to find and jump traces there, and come out of the board on a new wire bypassing any damage. 1/2 hour work once the SAM is on the bench. (Assuming you know how to repair boards and have done a SAM before so you know the assembly tricks. It took me a full hour the first time I did it, I could do it in a 1/2 hour now.) Enough cars have had problems I did a nice how-to.

In general I stay away from any damage involving chips and that intricate maze of hair-like traces. A big power chip or connection pin that's self-combusted is obvious and easy, the control sides I don't even touch. The reliability is too compromised, at least for the industrial machinery I work with. You think dis-obediant lights are bad, try donuts flying out of production, a truck waiting and the wrapper being moody!

[smartme 6]

After first repairing my SAM, the right turn signal lights were flashing very quickly.

Mine's flashing very quickly too with no burnt out bulbs that I can see, so maybeI have corrosion in my SAM as well. Need to study your info more and get into itsometime in Winter when we park it. Edited August 19, 2013 by smartme

[smartdriver 49]

Mine's flashing very quickly too with no burnt out bulbs that I can see, so maybeI have corrosion in my SAM as well.

It is possible that the white connector N11-9 has corrosion on it.If you are presently driving your car in this condition you are running the risk of damaging the connector through resistive overheating.I would recommend at the very least dropping the SAM down and inspecting the connectors.A spritz with some type of contact cleaner-lubricant would also be prudent.There seem to be many cars with this type of problem and I find it difficult to believe that all of them have leaks that would allow water in.Condensation from the air-conditioning seems to me to be another alternative.

[MikeT 744]

Mike's is very repairable.

That's good to know, so maybe in 10 years I can use it again.....

[smartme 6]

I would recommend at the very least dropping the SAM down and inspecting the connectors.

OK, will get on it just in case, thanks smartdriver.

[Alex 21]

That's good to know, so maybe in 10 years I can use it again.....

The lesson here is to repair it between year 7 & 8, then it'll be ready when you need it.Although adding those relays would render those particular connections immortal. No point for mine, all three of the problem wires are bypassed now and the SAM should be good until an entirely different failure occurs.

[MikeT 744]

The relay job for the headlights is on my list of things to do. However, I have 2 years' warranty on the new SAM so there's no rush

[smartme 6]

If you are presently driving your car in this condition you are running the risk of damaging the connector through resistive overheating.

My mistake as I checked everything again and the left upper rear light is the culprit.Missed that the first time for some reason.

[smartdriver 49]

My mistake as I checked everything again and the left upper rear light is the culprit.Missed that the first time for some reason.

Great news!That means, of course, that your connectors and SAM are likely all OK.

[smartme 6]

Great news!That means, of course, that your connectors and SAM are likely all OK.

When I finish the roof on my house, I'm still going to pull the SAMand do a thorough inspection now that I know just how muchproblems it can cause.If you can recommend a contact cleaner/lube, please tell meas I want to do a good job of it and wiring etc I've done oftenbut still not too competent with it. I'm still trying to figure outhow to wire the relay to take some load of the SAM.