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King of Smart Gadgetry
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Discussion Starter · #1 ·
Right after I got Max I wanted to do something about those open ends of the DeDion axles that you could see from under the back of the car. I decided to find me some caps and installed LED's in them, and i did.
2 were facing to the rear and they are the brake/turn signals.




2 on the outer edges are the parking lights.




And the 2 in the middle I connected to shine out from under the car when the dome light was operating.




Well since I was already tapping into the taillights to do this I thought I might as well add the 4 wire trailer connector. Well that is what I did. Well fast forward about a year and a half. As I said in another post the wife bought a novelty propeller that sits in the hitch reciever for 10 cents at a yard sale. I needed a bicycle carrier and need to use my little 5 X 6 trailer, so I bought a Curt hitch and proceeded to install it by myself. Now the hitch isn't real heavy but manhandling it on your back up under the tight quarters of the Fortwo isn't easy, and to add to my grief I had a group of wires that I had ran down to the axle for my beloved LED light caps. Now I protected the wires in wire loom and had to allow some slack in the wires because the axle does move(imagine that!). I managed to break loose a couple of the LED's on my driver side axle cap.
Now I had a mishap or two over the past year and have broken a couple of the LED's because they are not designed for what I am asking of them. They are quite low to the road and very susecptable to damage. I didn't glue them directly into the axle cap. I cut off the tip of red wire nuts and secured them inside the wire nut and then secured that to the axle cap.
But anyway I discovered that Smart likes to fuse everything differently and while a typical car gets a short in the brake lights, you blow the fuse and the brake lights go out. Smart took the approach to fuse the left and right side separately so if you short out the left side, the right side will still work. I did that a time or two in the past breaking an LED and it blew the fuse. So I repaired the broken LED, replaced the fuse and Max was happy again. But this time when I installed the hitch I noticed afterward I had knocked one of the LED's out of it's socket and after a quick run to the store I had a right turn signal but not a left.
The way it tells you that it's burned out is the turn signal indicator on the dash for that side doesn't light up at all. Well I headed home and dug out my fuses and I knew that the left side fuse was a 7.5 amp and was fuse #7 . Right side is fuse #6 , been there and done that. I pulled fuse 7 and looked at it and it wasn't burned out. I was shocked (not literally of course). So I put the fuse back in, turned on the key and hit the left signal. It flashes once and then no more. Cancel it, flip the lever again and still nothing. I can turn the ignition off and back on, then hit the left turn signal and get one flash and then no more, just as before.
I have come to the conclusion that the SAM is shutting down the left side. The Sam keeps track of resistances in the lighting circuit I guess (Can Bus). When I first got the car and needed the air bag light reset I took it to my nephew and he put his code reader on it and there were codes in the computer that said resistance in the right headlamp is out of spec etc,...(from where I installed LED's in place of the incandescents). So I am going to go and try to figure this one out. If there was a short from the broken LED the fuse would have blown. But apparently there is an open circuit to the LED I knocked loose and the SAM picks up the difference in resistance and as a precaution shuts down that circuit.
I added the load resistors that you must use to prevent hyperflashing. Can Bus is truly an amazing system and it sure keeps things interesting in my Fortwo. Gonna go try to trouble shoot this and get that left side working. It might be as simple as being low on blinker fluid...If I can only find the fill tank for that side. I will report back. DCO
 

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King of Smart Gadgetry
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1,094 Posts
Discussion Starter · #4 ·
My research leads me to believe that the blinker fluid used in the Fortwo is a unique blend only for the Smart brand. Legend has it that is a genetic compound made from the DNA of Nicolas Hayek. Now for you newbies who don't know who Nicolas Hayek is, look him up on google and you'll understand the answer. DCO
 

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King of Smart Gadgetry
Joined
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1,094 Posts
Discussion Starter · #5 ·
I crawled under the car this evening and I did in fact break one of the LED's on the axle cap. When it broke and raised out of it's socket, one of the leads broke. I soldered in a new one and super glued it into place. I then turn on the ignition and hit the left turn signal and it blinked. So I looked up to the sky and thanked Nicolas Hayek.
So I am guessing that was the problem. Maybe that's why we've heard talk about the need to use the "Can Bus error cancellers" . I bought a set to run inline with my HID headlights when I installed them. I don't know for sure what's sealed up in the little box, but it does work and the SAM is none the wiser. I guess it has to do with measuring resistance in the circuit.
 
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