
I'm sure most of you recognize this little rat nest...where the crankshaft speed sensor and the cylinder identification sensor meet the wiring harness. Our engineering friends at BMW cleverly decided to use the SAME connector for both sensors, and thought that if they just made one set of bracket cutouts upside down, you couldn't mix them up. Well, that usually works if you are just replacing one sensor at a time. The problem is I am in the middle of a full rebuild with both sensors off the engine. I realized the sensor lead lengths were long enough that they were interchangeable...bad news. OK, the next step was to pull back the rubber boots on the harness plugs and check the wire colors, then go to my official electrical manual to see which was which. The first plug had black, yellow, and grey...so far so good. The second plug...had black, yellow and grey....I could hear legions of BMW engineers laughing at me! The next step was to trace where the wires went, so it was back to my trusty electrical manual. Lessee...the black wire from the cylinder identification plug goes to pin 8 of the Motronic (or is that Moronic) unit, the black wire from the crank speed plug goes to pin 47. Next step is to pull out my Fluke meter and set it on diode mode...first plug black and check at pin 8...BEEP...success! I added some dots of color to each connector so this can't confound me in the future...that is, if I remember to write my color codes down somewhere safe (so safe I will forget where I wrote them by the next time I do this...it's fun getting old!)
Comment