1996 Toyota Landcruiser HU

I installed a Alpine 7997 into my '96 Toyota Landcruiser. The vehicle has nine speakers that I counted. I also used a metra radio harness for the install. There are 3 connectors at the factory harness. One was plug into the factory radio and two were not being used but were the only ones that accomodated the metra kit.  I assume one is for the factory amp( the one plugged into the factory radio) and the other two are for directly into the speakers. I used the two that I assume are direct. There are four sets of speaker leads and  tested the speaker leads and are each at 3.9 ohms at each corner. So I assumed it is okay to wire it like a normal install. My dilema is that the radio heats up really fast to the point that it blows the fuse at the radio. The other problem is that the radio does not seem to want to stay on. It will turn on for a second and then turn off. I wired it directly to the battery and that seem to solve the problem.  Anyone have any ideas or tips?

Where are you grabbing your ground from ?Jeff

Velocity Custom Home Theater

Mobile Audio/Video Specialist

Morden, Manitoba CANADA

I grabbed the ground from the factory harness.

The unit is an Alpine 7897 not 7997 if it makes a difference. Am I missing another piece to the harness kit?