the end of this thread has a diagram that shows the pin connectors, but it doesnt help, because it is wired correctly and is still quiet.
http://www.toyota-4runner.org/3rd-g...ble-finding-correct-radio-wiring-harness.html
I am not saying you are wrong, but send me a picture of your wiring harness as connected and Ill see if I can help.
Mismatching speaker wires can cause this as I have seen this before in my previous life as a car audio installer.
Do you have a factory amplifier?
as I said above, I took the factory amp out.
I just went back and looked. Crutchfield sent two harnesses/plugs that match the factory amp plugs, one small for the rear speakers, and one larger one for the front speakers/everything else. I had wired the speaker wires from both connectors to RCA's and plugged those into the back of the head unit instead of wiring the connector wires to the matching speaker wires on the head unit (i.e. how the previous aftermarket head unit had been wired) . I just resoldered it directly from the connector to the head unit wires instead of using the RCA's and it's fine now. brain rattling volume and all.
Glad you got it. Take it easy.
Just about to install my Kenwood as well,nice to see others here have them and are happy with them ,was unsure on my decision when buying a new HUI installed a Kenwood 1.5 years ago and ripped that stock amp out. The Kenwood sounds way better than the old system. My opinion is to dump the amp without thinking about it.