Does anybody know the cleanest way to install a sub in my 4runner as far as wiring? My current stock stereo does not have a subwoofer and I am looking to get the stereo signal to the back of the truck and was thinking of just taping off a rear speaker in parallel to grab the signal to feed the subwoofer. Does someone know if the 4runner is prewired with the subwoofer signal even if I did not get this option?
Does anybody have any information regarding how to remove the head unit and door panels on a 2005 toyota 4runner?
You will need to amplify the subwoofer. You can tap voltage from the OEM speaker wires and feed to a line output converter. This device converts the high level speaker signal to a low level line signal. With RCA plugs, the LOC is connected to the amp.
example of a LOC: https://www.peripheral-aamp.com/periph_products/line_output_convert.htm
You can pick these up at a local audio store. Get one that is touted as "high quality", as it will have adjustments that can be made. OEM audio systems differ from one another.
I prefer tapping (actually, soldering into) the front speaker wires for the sub. Then you will have the ability to fade the rear speakers out and not affect the output of the sub. The front speakers will continue to play as normal with power from the head unit.
-------------
Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.