I am just saying that on an 83sc the only black plug goes to the frequency valve, Bosch 0 280 150 300! Its below the throttle body along the fuel lines!


http://forums.pelicanparts.com/uploa...1361839451.jpg

Here it is mounted to the back of the throttle body!
http://forums.pelicanparts.com/uploa...1361839759.jpg

78/79 SC doesnt have a frequency valve, thats part of the oxygen sensor system
Bruce

Ok, the black plug goes on the AAR! I took pictures and as I said, on a 78 SC all plugs are color coded with their respective receivers so dummies like me don't mix them up (which I did do a year or so ago).. I'm amazed that they changed the color coding from 78 to 79 (as Sonnet's photo showed).. I like that they match!

Here they all are -

AAR Plug - Black
http://forums.pelicanparts.com/uploa...1361842344.jpg


WUR Plug - Grey
http://forums.pelicanparts.com/uploa...1361842377.jpg


Throttle Plate - Blue-Green (Flash makes it look like CSV color but it is darker)
http://forums.pelicanparts.com/uploa...1361842405.jpg


CSV Plug - Blue
http://forums.pelicanparts.com/uploa...1361842442.jpg

Interesting....I recently removed my airflow sensor on my '74 and there is a mystery plug attached to the back. Not the plug with the wires but the male-side that appears to go to nothing. Since my '74 wire harness doesn't seem to have the plug, does that mean my airflow sensor is from a later year?

Color of male and female connectors the same, what a great idea!
Those Germans.... :)
Wouldn't work on my car any more as the wur connector was broken and the only replacements available are black...
Glad you found where it goes. Hope it doesn't affect your idle and mixture too much...

Thanks.. get some paint and stripe those black connectors! :D