01 lexus is300, double din monitor

Hi im installing a jensen double din monitor in my friends 01 lexus is300. I got a metra 70-8113 factory amp harness for a local stereo shop. Plugged in all rca's wired all the power but the factory amp is not turning on im guessing. Checked remote and regular power at amp and is good. Heres the wierd part. On the back of the factory radio there were two harness's. One with like 15 wires speakers power etc. Then another harness with two wires. If i plug both harness's into the factory radio leave the key on without turning the key off remove both plugs and plug into new radio it works fine untill i turn the key of and on again then no power to amp again. The plug with two wires just sit there with the new radio the metra harness does not plug into it at all. Please some sugestions im stumped... Thanks

This amplifier uses a data turn on. Metra does make a digital adaptor for it. I believe the model number is TOY-CR01 but I'm at home now so you will have to look it up or call Metra tech. A couple of thoughts on this part, it will not interface with factory nav. and it has a small amount of untreatable engine noise in this car.There is no such thing as free installation!