2009 Ford Ranger Radio Help

Im working on my brother in laws 2009 Ford Ranger. Base model, power nothing,manual.

He installed an after market head unit and now when you use the radio it drains the battery overnight.

I checked the wiring and everything SEEMS in order except a solid blue wire coming from the head unit labeled "remote turn on". When the ignition is off there is no power there, when the ignition is on it gets power.

Im not sure whats going on here. It does not have a power antenna and its not labeled power antenna to power it up. 

My understanding is that it is used for amplifier turn on but i have no amps, only base model speakers. 

What is going on with this drain?

Whats the blue wire supposed to go to or get connected to?

Maybe it is not related to the aftermarket radio and something else is at fault?

Im at a loss. Please help me out

Alternatively some reading leads me to a power saver relay which could do the same battery drain

The blue wire is only to send a "power on" signal to an amp. If there isn't one, don't use the blue wire, just insulate it and tuck it away. As for the draw, pull the fuse for the radio and see if it still drains the battery. If so, you have a different issue. 
if the radio is indeed the cause of the draw, double check the wiring. Was the head installed using an adapter for the stock harness or is it a cut and splice job?

Head unit was installed with an adapter. Aside from some messy connections it was nicely done. The messy connections aren't the problem, just my ocd