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johndUKroadster

Wet SAM....turn signals will not switch off

9 posts in this topic

Hi All,

Wet SAM woes...

Recently I noticed the hazards turn on briefly then the horn go off on my way home and suspescted wet SAM syndrome even though I thought I'd fully resealed the car when the SAM was replaced 14 months earlier. Took SAM out even though the issues had stopped when I got home and there was some water in the box. Cleaned it all up and dried it all out and when I went to start the car all electrical hell broke loose....the wiper stalk even switched the car on!!?? So cleaned it all off again/dried it out and when I put the SAM back in the car I had a continuous left turn signal. Checked the stalk, fine. Unplugged stalk to make sure and the turn signal kept flashing. Took the SAM out again and I noticed a very small amount of copper oxide (less than any I've any seen in any pics of corroded SAMs) between the caps/resistors on the input stage so decided to clean between the components, with a jewellers screwdriver!!??, to make sure there were no shorts and then realised there were small tracks between some of the caps/resistors....doh! I also noticed one of the through holes was pretty crudded up so took the board to a local circuitry electrician and he repaired the tracks, through hole etc. Left signal still on!! Then the other day it decided to have a change and now it is just the right signal that is always on. Hazards work fine etc.

Can anyone confirm if this could be a short in one of the wires to the SAM, a bad ground etc etc? Just want to rule out the simple things before the SAM gets a thorough looking at.

I know on another thread it has also been mentioned that the 74HC151 chip could be at fault but there doesn't 'appear' to be any corrosion around it.

BTW this is actually a roadster but I know the units are quite similar.

Have hazard/turn signal DIY wiring kits ready in case I can't fix the SAM!!

Thanks

John

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Just to clarify, this is not a 451...? Because your post is in the 451 forum. :)

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AFAIK the 451 uses a SAM too, hence the post, and there isn't a roadster section.

Hope I can work out where the issue is as I know my electrical engineer contact should be able to repair it......unless it's on the microprocessor that is!! I'm leaning towards one of the 74HC151 chips as this is what sends the output signal to the indicator.

Also tempted to power up the SAM with N11-9 disconnected to test if it stops the problem. I'm pretty sure it's the output so should stop the signals but I guess the buzzer would still be going on the board.

Must get a magnifying glass out to see if there is any corrosion on the connector too even though it doesn't look like it and I did spray a shed load of contact cleaner in it.

If anyone has any ideas as to what could switch the signal on, aside from the SAM or stalk, such as a short that would be really useful and then I could check the simple things. The fact it went from left to right suggests to me it may be SAM related though.

Cheers

John

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I recommend you post on theroadster.net

Roadsters were not sold in Canada. My apologies for being unable to help.

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Hi All,

AFAIK the SAM control systems are the same and some of the same problems occur when wet. I'm just trying to build on the excellent info that Smartcardriver previously posted.

Incidentally I removed the N11-9 connector and the clicking/dash flashing still continued. The N11-9 receives inputs from the stalk and outputs to the lights so, in my limited electrical knowledge, this would suggest a short in the SAM tracks, chip problem, dry joint etc. If the microprocessor is knackered then I fear it's game over. If not it 'should' theoretically be repairable saving $$$'s over a new SAM.

John

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Yeah, I believe you're correct. At the very least, I'm pretty certain the roadster SAM is the same as the 450 SAM. My personal guess is that there's a bad solder joint or cracked trace somewhere, rather than the micro itself being toasted, but it's pretty hard to diagnose online.

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Not directly related to this but I am waiting for my third SAM for my 2005 cab. I just filed a complaint with Transport Canada as these failures are far to common and dangerous. My wife was driving on an expressway when she lost most of the electricals and had a very anxious moment to clear the road. Enough is enough.

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Again external relays save the SAM. . Should of done that on your first replacement and I believe the dealership did a tsb regarding it. My bet if you replace it again you'll have the same problem down the road if don't install external relays and take those loads off those contacts.

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