Sam Unit

[smart142 605]

Recently I am a little distressed because the SAM units are giving me grief. It seems that the relays to the fuel tank pump and headlights are failing.Looking at the unit will show that it would be difficult to repair. The relays are on the backside, and to get at them, the unit would have to be unfolded.The ribbon wire fold looks to be deteriorating with age and looks very fragile.I'm attaching pictures that show the SAM unit from a parts car that should illustrate the problems.A solution to replacing the relays would be worthwhile because a new SAM unit from the dealer is about $1600 installed.

[MikeT 744]

That is why fitting external relays to the constant duty cycle units such as DRL and fuel pump is a good idea, as a prophylactic repair. My car now has the fuel pump external relay but soon I will want to add headlight external relays.

[CANMAN 23]

I used one relay to power both low beams and one relay for the fuel pump.They are mounted beside the yellow relay.CANMAN

[David_18 13]

I am not sur to understand how the external relay work.. ??The Sam no longer manages the lights and the pump?

Edited January 30, 2014 by David_18

[MikeT 744]

The SAM only takes a small load, with the major amperes going through the external relays.

[David_18 13]

Some body have a tutorial for doing that?

[marchanna 115]

Is there a space already there to mount the relays or did you have to fashion something up for them?

[Alex 21]

There is room for them, but no nice pre-drilled rail. Mounted is nice and neat, easiest would be to Mac-tac (double-sided foam tape) them to the top of the SAM case, but then you need disconnects from the harness. Or zap-strapped to the wiring bundle. Mac-tac to something else up there. Get creative! The common 30-40 amp automotive accessory relays are ideal, common and cheap, no exposed live parts so they can just hang any old way. (Serious off-roaders may disagree, but we are talking smartcars here!)

[CANMAN 23]

Is there a space already there to mount the relays or did you have to fashion something up for them?

Depends, if you have heated seats or not, and your level of skill and the amount of patience you have.If you look at my picture above I mounted my relays beside the yellow factory relay in the place the relays for the heated seats go.It was a very difficult installation with limited space to work and the requirement to completely remove the SAM.Do not cut the strap tie mounting the relay portion to the metal bracket, it is almost impossible to get the relay housing back into place.The SAM separates from the relay portion.Much easier to strap tie the relays to a wire bundle.Canman

[dieselkiki 7]

I still don't know why smart engineer choose to replaced the previous fuse/relay box (avaiable on pre 2003 fortwo's) by the actual "fragile" SAM box. Actualy we need to modified the original electrical system and instal extra relay to improve the reliability of the electrical system when the previous system was exactly built with externals relays. Why? Was it too much reliable?

[FlossyTheSmart 81]

They probably thought this new solution was "good enough". Consider that these issues aren't happening on all smarts, and on the ones it is, it worked for at least 8 or 9 years. They probably thought it would last long enough, and that it simplified assembly to some degree.

[Smart_guy 2]

So relays are pretty basic and easy once you understand them. Most of them have a diagram on the side and the terminals numbered. There are a few variations but the basics are the same and they all seem to use the same number ID's. This is the relay you would get at an aftermarket parts store. It comes with the connector and pigtail (section of wire)

[Smart_guy 2]

So you have 5 terminals on this relay. #85 #86 #87 #87a and #30The control terminals are 85 and 86. This is an electro magnet. When power and ground are added here it pulls a lever to make contact with a terminal that normally does not have electical power.

[Smart_guy 2]

So here is where it gets a little complicated. #85 hook up your controlled power, head light switch or ignition switched power. What ever you want to use to activate the device you are looking to control. So for a fuel pump you would connect to a power source that is on when the key is in the run position, and the start position but no power when the key is off. #86 gets hooked to ground. So a wire going to a good ground source. Once these 2 are connected you should hear the relay click when activated#30 is your supplied power. So in case of the fuel pump you would want to hook to a fuse location near the coloured fuses on the side of sam (some of these are connected to ignition some are always on, be careful) To be safe add an inline fuse here so if something goes wrong there will not be a fire. Now in that diagram you see the line that goes from #30 up to the dashed line, that is a pivot point. When the relay is at rest (not on) power is able to flow from #30 to #87a. Then when you turn the relay on that pivot connects to #87 not #87a#87 Going back to the fuel pump, the wire you cut from the connector that burns should be connected to #87. Now when you activate the relay power flows from #30 to #87 and the fuel pump should run. #87a is typically not used much at this level. I can keep explaining but want you all to be able to install a relay confidently. If you want the explaination let me know.Now if you are wondering about the drawing, the squigle from 85 to 86 represents a load (the electric magnet)The box over that is a diode that prevents voltage spikes from feeding back when you turn the relay offThe dashed line represents the moving part of the relay. It is a magnetic lever with a contact point that moves from 87a to 87 when the relay is turned on.

[smart142 605]

Troy!

[David_18 13]

Is that right ?

#85 : Power when ignition is ON (Split N11-4 - 1)

#86 : Ground (Any ground wire ?)

#87 : Go to Fuel Pump (Cut from N11-3 - 10)

#30 : Fuse Box - Power when Iginition ON (Hook to Fuse #?)

Not sure if it is the right SAM Unit for Canadian smart..

http://www.evilution.co.uk/index.php?menu=...uts&mod=930

Edited January 31, 2014 by David_18

[Alex 21]

Excellent explanation, Troy.just one tiny correction, because the coil connections are not marked for polarity, we know that the spike-absorbing device (the box over the squiggle) is a snubber, not just a simple diode. Various internal designs, details would confuse matters. All we know for sure is that polarity would be clearly marked if it mattered.

[Smart_guy 2]

Damn, burst my bubble Good catch on that one Alex.ThanksDave I don't know the exact pin numbers but Im sure someone will verify that for youFor ground I would recommend just running to a ground point or making a ground point

[turbomar 13]

Here's another choice of relay:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewI...atchlink:top:en

Less than half the size with same Amp rating. The good old bosch is great but when space is at a premium, I use these.

@David

the 4 fuse holders nearest you on the side of the SAM are switched live, the other 5 are constant live

Edited February 1, 2014 by turbomar

[Utopiacdi 3]

Excellent Troy. Thanks But a question...is there a connection to 87a or is it left bare, so to speak?

Edited February 1, 2014 by Utopiacdi

[turbomar 13]

Center terminal is not used

[Styvon 3]

I found my SAM almost like picture....

P0003 code... nothing else...

1600$

[MikeT 744]

I had a SAM change in my white car and with labour it was $1500. Yeah it's not cheap!