I have installed a Double Din Planet Audio head unit. I used the Metra 70-1858 wiring harness. I have done dozens and dozens of stereo installs and have never come across this problem. I connected all of the wires to the colored wire in the harness and every morning I wake up to a dead battery. Is it possible that since I went with such a cheap head unit that it could be causing the problem? I have installed the OEM head unit and the problem has gone away so I know the battery going dead has something to do with the new install.

 

The first thought that comes to mind in these situations is that the ignition switched power and constant (battery) power have been reversed. That's rather unlikely when using a wiring harness adapter but it never hurts to double check. The factory harness uses the yellow wire in the black 10-pin connector for ignition switched power and the adjacent orange wire for battery power. Those should correspond to the red wire (ignition switched) and yellow wire (battery) in a standard aftermarket harness. Having them reversed won't actually hurt anything but can cause much greater than normal current draw while not in use.

 

Thanks for your response. I found another one of your threads and I have taken out the ACCY Radio fuse just to make sure this is where the problem is. Wiring has all been done correctly and usually this is a straight forward process, but it doesn't seem so this time.

 

The RADIO ACCY fuse protects only the Monsoon amp and is unrelated to the head unit. It will have constant (battery) power because the amp switches on and off based on sensing audio signal from the head unit. If the amp was the problem then switching back to the factory head unit would not make any difference, but it did.

If you want to confirm that the new head unit is causing the current draw then the RADIO fuse is the one providing ignition switched power to the HU. You should pull that fuse and see if the drain continues. That will tell you whether the new HU is the problem. It is also possible that the new HU is drawing too much power through the constant (battery) connection which should only be maintaining the clock and settings memory. That circuit flows through the PWR ACCY fuse. If pulling the RADIO fuse doesn't resolve the drain then you could try pulling the PWR ACCY fuse instead.