I ended up jacking it up and going throuh the wheel well.That was how I was able to see it had a tab to depress. It was facing right towards the wheel well and I depressed it with a small screw driver and it released the plug.It is still not easy to get the sending unit in or out I did that from underneath with a ratcheting wrench.you have to bend the lip of the plastic drip tray out of the way to get it on the sending unit.I faced the tab down when I reinstalled the unit for easier access next time.If you have the new sending unit you can see where the tab is,it goes into that square hole on the side.Look at the one your truck it should be in between the 2 plastic ribs on the unit and may not be facing the sameway as mine.You may not have to go in through the wheel well.I probably wouldn't if I had to do it again,Now that I know that tabs there and could get to it from the bottom it would take me about half the time.You might as well change the oil and filter while you there.Like I said it took care of the low oil pressure light and gauge when cold. Its never a good feeling to see no oil pressure even if your pretty sure its the sending unit Have fun.