I have the exact same issue!

https://diagramweb.net/kenwood-kdc-mp245-wiring-diagram.html

Hook up the power source to the battery, wire in some speakers.

if its anything like my 92 ranger you take the dash apart around the radio and the stereo should unscrew, in my ranger the new cd player went in without any extra harness as it was the same size as the stock, if not you can but harnesses to go where your old stereo did, to connect the speakers you can buy a ford wiring harness from walmart or any store with an audio department. these plug in to your vehicles wiring harness so you don't have to cut it out, after that you simply match colours from the wires of the new cd player to the wiring harness

Hi there,

YES.... to prevent cutting of any factory wiring (this use to be the old install method and requires much more time and expense) and potential electrical fires, you can now buy quite cheaply, what is called a Radio adapter harness.

As you wish to install a Kenwood radio to your Toyota Scion, simply buy an adapter loom which has a 2005 Toyota Plug on one end, with a Kenwood plug on the other (this essentially replaces the wiring loom that came with your Kenwood unit).

So, it's that easy .... Plug and Play.

And... if you sell your Toyota and wish to put your old Toyota radio back in, the original radio just plugs back in. PRESTO !


Hope this helps..

Cheers,

Scott

The installation instructions begin on page 20 of the manual.

You can get this part from strereo install shops, they have tons in stock, usually.

locate the reset but on the face or behind the detachable face and hold it down for 10secs. its is the size of a pen tip.

The KDC 334 doesn't have any audio input, so there's nowhere to hardwire an iPod or other mp3 player into the unit.

I'm sorry, but the only way to get iPod sound to come through this head unit is with a wireless gadget like the iTip FM adaptor.

This is a link to Kenwood for your KDC-135 Owners Manual. Page 15 has the wiring diagram and pages 16 and 17 cover physically installing the unit.
http://www.kenwoodusa.com/UserFiles/File/Global/Consumer/Manuals/KDC-135.pdf

wiring diagram or colour code for kenwood cd player model kdc-5108