blue plug behind radio

My friend got a 98 tacoma from auction with low miles but the radio gear has been removed. I see the 2 plugs that go to the factory radio, but there is a blue plug with a single wire on it and it has been cut. What is this wire\plug for? I was thinking the accessory outlets but I haven't taken anything apart yet. Thanks for any info

 

What are the colors of the single wire? We could look that up in the factory wiring diagram.

 

I want to say white with a green stripe,I don't have the truck here right now. When the aftermarket radio gear gets here in a few days I can confirm

 

It is a white with green stripe, ive got it too, just hanging out. It should be an illumination wire. Green with red and white with green are illumination wires in the harness. I never tested mine to confirm this though...

 

Just checked my FSM, and white/green wires do appear to be the grounding half of the dash bulb wiring.
If its a single wire, and is 'cut' as the OP says, then what is hanging on to it?

Could be for a bulb in the HVAC controls or perhaps an optional ashtray bulb?