2012 AC Clutch Wire Location/color

1895 Views 9 Replies 4 Participants Last post by Beryy2, Sep 6, 2021

Budd

Discussion Starter · Aug 30, 2021

Does anyone know if there is a wire that goes to the rear to activate the AC clutch? And where can I tap into it and what color? It appears that my SAM is damaged and will not activate my radiator cooling fan. I cleared a fault that was caused when my fan locked up but the fault keeps coming back and the new fan won't come on - no power. I am installing my own circuit and want to turn on the fan when the AC clutch is engaged on my 2012 Smart Passion
I am hoping I can tap into it somewhere in the harness that is in the battery compartment, if so anyone know the color or some way to tap into it? I know I can do it with a switch, but I really would like for it to come on automatically when I turn the ac on. If anyone has a better idea how to know when the AC is on please help. I was really hoping I could find something at the SAM/Fuse Block. I bought a good Scanner (MK-808) and it does clear it, but comes right back.

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Budd

Discussion Starter · #3 · Aug 30, 2021

It shows a N10 SAM code fail, I have reset it many times and as soon as power is turned off and back on it shows that failure again. The fan fail does not show a normal OBD fail code, my $500 (MK-808) scanner does. I removed the SAM and opened it, all connections look good and are all clean, nothing appears burned. I did go ahead clean them even though they looked good. From everything I have read the SAM is not serviceable. I am still looking for the wire for the compressor clutch.

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Budd

Discussion Starter · #4 · Aug 30, 2021

jwight said:
Are you positive the SAM is damaged? Might be worth chasing down the actual problem rather than trying to rig up some workaround. Are there any associated OBD codes?

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Budd

Discussion Starter · #6 · Aug 30, 2021

vadsoom said:
The AC clutch wires is SAM connector C10, terminal 2 and is a white wire. Here’s the schematic…

Thank You; you know I looked at that but wasn't sure. I think this is the same as mine it's marked N11-10?

Roadster SAM Wiring

The home of modification and maintenance for your smart.

www.fq101.co.uk

I'm getting there, I bought a cheap temperature switch which will turn on and off the fan with temperature but the AC condenser needs cooling almost any time the AC is on in the summertime in traffic. I also have a switch where I can turn it on whenever, but I wanted it to be automatic without remembering to turn it on.

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Budd

Discussion Starter · #7 · Aug 31, 2021

Budd said:
Thank You; you know I looked at that but wasn't sure. I think this is the same as mine it's marked N11-10?

Roadster SAM Wiring

The home of modification and maintenance for your smart.

www.fq101.co.uk

I'm getting there, I bought a cheap temperature switch which will turn on and off the fan with temperature but the AC condenser needs cooling almost any time the AC is on in the summertime in traffic. I also have a switch where I can turn it on whenever, but I wanted it to be automatic without remembering to turn it on.

In looking at it closer there are wires that are different colors on the Roadster although some are the same, I haven't looked at many of them but...

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Budd

Discussion Starter · #9 · Aug 31, 2021 (Edited by Moderator)

vadsoom said:
Sorry, Budd, I did not realize you were working in a roadster. I hope the schematic is close enough to help.

In the case of the 451, the radiator fan turns on when the AC compressor is on, not not constantly. Before ripping the system apart, I suggest you have the AC serviced. There are a few parts in the AC system that work in conjunction with each other. If something is amiss, the system may not work as expected.

Just recently, I serviced my AC system. Prior to doing so, my cooling fan was somewhat erratic. I think the AC pressure may have been a bit low. After system service, it appears to be working better.

When I suggest service, I’m not just recommending to add a can of R134A - that can result in overcharging, overtaxing the compressor, inefficient cooling, and the inability of the condenser to return the R134a to a liquid state. In other words, overcharging is often times worse than undercharging and can result in damage. A sufficient undercharged system will simply not allow the AC clutch to engage and the system won’t provide cooling.

I hope this helps

No you are right, it's not a Roadster - it's a coupe. I was looking to see what connector you were talking about before I took the SAM back down. It looks like the SAM for my 451 is the same as what I found for the Roadster except for some of the wire colors. This all started when I bought this Smart Car as a fun thing, the AC was cycling on and off like it was low on Freon, turns out the radiator fan was bad. The AC condenser must have air cooling it either by driving or by having the radiator fan blowing across it. I replaced the fan and it still would not come back on. In reading other comments here I learned sometimes the SAM will go into a fail mode when it sees the fan pulling to much current. I bought a MK-808 scanner because a cheap scanner wouldn't work on a Smart (Mercedes) Car. So that's where I am at. I wired it so I have 3 switches; 1 to turn on the temperature controlling circuit allowing the fan to cool the engine as needed; 2 to turn on the fan manually, and this third one will turn on the fan when ever the ac clutch is on. That will provide air through the condenser for the AC. All will shut down when the ignition is turned off.
As far as the AC, I evacuated the system, pulled a vacuum and then charged it to to the Freon weight as called out. I have a complete AC service system, reclaim pump, reclaim cylinders, vacuum pump and a scale to insure the proper amount of Freon is put in. From what I have read is the radiator fan should be on anytime the AC is on. I jumped the fan wires and with the radiator fan on the engine temperature is good and air flowing across the AC condenser allows the AC to work perfectly. When I scanned the car it showed a Fan fault, I cleared it and the fan should have come on as long as the AC is on in the summertime. The failure keeps coming back and the scanner shows it as the SAM being bad. I new SAM is around a $800 to 1000 with programming with no installation, my new circuit will act like it's being run by the SAM and the cost is about $25 plus my labor, but being and old retired guy that spends many hours in my garage....

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