Help Identify GM Oxy Sensor

[choco]

G'day everyone, long time, no see!
I have a GM Oxygen Sensor that I bought new from eBay, and I need to identify the wires. The part number is AFS 109, it is quite a common 4 wire O2 sensor in GM cars. The wire colors are brown, brown, tan and purple. I need to know what the wires do, like which ones are the heater wires and which ones are the sensor and sensor ground wires.
If anyone can help, there will be free beer tomorrow!

I am coming over to Seattle sometime in the new year to fit a EFI converted stack injector to a friend's Cobra (in Redmond, aka Samamish). I hope to look up some PNW RRTers while I'm there!

BCNU

[oiler]

Here's the pin locations and functions Choco.
The colours don't correspond to your O2 but the pin locations and functions are the same if it's a flat 4 pin conn. or a square 4 pin conn.
pin A- low signal ,tan
pin B - high signal, purple
pin C- Ground , black
pin D - ignition 12 volts pink

[choco]

Here's the pin locations and functions Choco.
The colours don't correspond to your O2 but the pin locations and functions are the same if it's a flat 4 pin conn. or a square 4 pin conn.
pin A- low signal ,tan
pin B - high signal, purple
pin C- Ground , black
pin D - ignition 12 volts pink

Thanks mate. Free beer tomorrow!