Radio Wiring Harness PLEASE HELP!!!

I have a 95 Tacoma Reg Cab 4x4 with the 2.7L engine. All of the websites i have read say that the blue/yellow wire is the 12v constant and memory for the harness, problem is that my truck has no blue/yellow wire and ive even put a test light to every wire in the harness and none of them have power when the truck is turned off. there is a grey wire that does have power when the acc is on but thats the only one. if anyone has encountered this problem please let me know how you fixed it. thanks.

 

The main power lead to a 1995.5 factory radio is a grey wire. It should trace back to the 7.5A RADIO fuse.

The light blue / yellow wire is not the power lead to the radio unit - it's the power source for the radio illumination.