Mystery plug under rear seat

02coastie

02coastie

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Can anyone ID the purpose of this plug on my '74? I don't see anything for it to connect to. From what I can tell, everything is working as it should, but the cut wires give me pause. The only thing I can think of is if BMW used a single harness for both CSI and CS's, and this is for the brain.
Thanks!
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very strange
i would think its for the csi w/ a brain
as there's nothing else that could go there
my 74 does not have it and its carburated
 
CSi ECU plug is 4 x 1 inches and has something like a 72 pin connector. The ECU is located under the rear passenger seat.
 

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For the record, this is under the driver's side rear seat. Based on adawil2002's post, it's not a CSI connector. Any other thoughts?
 
Could they be from an old amp or a sound system? Originally thought they were for the pressure pad seat belt lock buzzer system that illuminates the FASTEN SEATBELT warning on US coupes.
 
adawil2002 said:
Could they be from an old amp or a sound system? Originally thought they were for the pressure pad seat belt lock buzzer system that illuminates the FASTEN SEATBELT warning on US coupes.
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I can't imagine the former. They look to be factory wires. The weird thing is that the black (and likely positive) wires are all cut. The brown grounds are all intact.
 
Some of those colours look like electric window colours...... ? I agree probably an amp or something, but did they fit factory ones, even that late?
 
Factory did not install amps. Could they be electric sunroof wires, colors are similar? And they would go up C pillar.
 
That connector was one of the first mysteries I came across on my '74. Under the driver's side rear seat, right? I believe pretty strongly that it's for the seatbelt chime / light. A few of those wires would be for the lamp on the dashboard, a few for the occupant sensor switches under the seats, a few for the switches in the buckles themselves.... But then again, I haven't made an effort to restore that system! I can upload a picture of the module that was plugged in when I got it if you'd like. Googling the numbers stamped on it didn't help very much as I don't think it's a very sought-after part.
 
My car is a 72; so I don't have whatever that may be. I have had some luck identifying electrical parts using the wiring diagram and working with the colors of the wiring that runs into the connector. Each connector has a unique combination of wires, and the wiring diagrams in our owner's manuals are excellent.
 
1974 was the only year the Fed required seat belt interlocks to start the car. Not sure if BMW had to succumb the same regulation given the low numbers.
 
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