MAF Signal Wire?

[Bama_Z4]

I need to do some testing on the MAF sensor. The wiring diagram shows two wires running from the sensor to the DME.

Both are labeled as "MAF SENS" and run to the DME. One is Yellow, the other is Red/Grn.

Which is the signal wire? And what is the other wire for?

 

[colb]

useful thread with wiring diagram here https://www.zpost.com/forums/showthread.php?t=1685431
Some models of Mafs are duel purpose and also measure intake air temp since yours is just two wires it isn't one of these.
Yellow on yours is Maf signal
Red/Green is Maf supply

 

[Bama_Z4]

Thanks colb. Very helpful!

If R/W is my 12v power supply, then what sort of "supply" wire is R/G?