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SM Wiring on USA Models


As noted in other sections of this article, the wiring was different on North American models. Some of the differences include side marker lights, headlights, the door buzzer system, the seat belt warning system, hazard lights, electric antenna wiring, and leak finder wiring.


A set of schematics have been found that show USA model wiring. These schematics should be applicable to 1973 Canadian SM's as well. However 1971 and 1972 SM's in Canada are a bit of a hybrid between USA and Euro wiring.

I created a 'key' for these wiring harnesses. If readers spot any errors, please let us know and I will correct it.

Key for Schematics (click to open)

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USA Harness Schematic (click to enlarge)

SM USA harness schematic.jpeg

USA Functional Schematic (click to enlarge)

SM USA schematic functional.jpeg

Note that these schematics do not include wiring associated with the seat belt warning systems and for the Borg Warner automatic transmission. (See the next section.)


I found a few more wiring resources for North American cars. We found an extract from a service bulletin that has some information on wiring associated with the Borg Warner automatic and for the air conditioning HERE.



Since some of the North American wiring is not shown on the schematics, we have attempted to help identify some of the unique components behind the dash....

We finally found a schematic for the seat belt warning system for the SM. It is very similar to that of the DS and uses most of the same parts, but the SM apparently has a relay in the system that the DS does not. I am not sure where this relay resides in the car and frankly, if you look at the schematic, I think that the relay might be drawn wrong internally. You can see the SM seat belt warning system schematic HERE. You can see a video demo of the seat belt buzzer HERE

Behind the Dash on North American SM's

(click to enlarge)

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George Klein

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