Installing A KDC MP438U Into A 05 Corolla

I decided to get Pam, my girlfriend, a car stereo this year for Christmas. Unfortunately, she couldn't use her factory 6-cd changer anymore when some of the discs I made for her got stuck in the unit, unable to be dislodged.
So I decided to get her a new unit alltogether. I haven't ever replaced a car stereo, so this was done with a little uncertainty. She has an Ipod, so I decided to find a head unit (the proper name for a car stereo) that had not only an Ipod input on it, but a USB port as well. The answer: the Kenwood KDC MP438U.

This is what the old factory unit looks like from a rear view:
With the hu (head unit) removed from Pam's car:

I admit: The plugs situation sent me to the internet, and then a local car stereo installation shop to find the answer. I needed a specific wire harness that was custom-made to fit the plug assembly for her make and model of car.
I purchased an 05 Corolla (6 JBL speaker) plug assembly for 17 dollars at the local stereo shop. Otherwise, I didn't need to purchase anything else, other than the din unit (dash kit) and the stereo.

The attendant at the local car stereo shop was glad to show me the harness I was wanting, but suddenly, after pecking around on his pc keyboard a bit before ringing me up, he gets a serious look on his face, and told me that he's supposed to include a $110.00 pre-amp digital converter if my girl's car was a 6-JBL speaker setup. It was, but this new amp device was news to me. All of the research I'd done, plus seeing the plugs as they were originally plugged, told me to resist his hard sell.

I quickly steered the conversation into deeper details, ("Well, why does the 6-speaker assembly need a digital conversion that the 4-speaker wouldn't", etc) mainly out of shock at the price of this device, and had him unable to answer me within a minute or so. He finally said, "Look man, all I know is that if your stock stereo has inputs like the ones you got in this picture, here", [I printed off a copy of the above photo with "05 Corolla stock radio" in it to illustrate my job needs when I went to the shop], pointing not to the ones that are circled in yellow, but to the ones on the left side of the rear of the stereo, "then I'm supposed to include this amp convertor".

That port looked more like the port on the back of the new Kenwood, and I had been wondering why there was nothing plugged to them when removing it. But the ONLY plugs (besides the antennae) from the Corolla were the ones circled in yellow above, going to the yellow-circled ports above that pic. Nothing was plugged into the left-side ports, and I told him that twice--once in the beginning, then again now.

He said, "If you didn't have cables running to that port, then your car ain't a 6-JBL speaker system--it's a 4-speaker system." triumphantly, with finality, as if there was no more left to say about the matter.

I told him, "I'll take my chances, let me buy the 17 dollar JBL 6-speaker harness for now, and if I need to, I'll come back for that amp convertor."

The new harness is to be connected to the one your radio manufacturer sends you. They look similar, but with different plugs, of course, and maybe some labels, but they are using universal colors in the car stereo industry, so you just merry up color to like color. This is the Kenwood harness that came with the package:

My advice: crimp (with butt joints, not crude splicing with electrical tape) the new assembly to the new stereo wiring harness, which should be included in your new stereo packaging:

After crimping, attach them to the car's harness:

Before attaching the wires:

After plugging in your antennae (single-post adaptor, usually), plug in your new hu:

Slip it in, and carefully snap the dash console back in place:

And VOILA:

All works great, and she's really impressed with the upgrade. I'm happy--she deserves to have nice things. We particularly like the USB port capability, and the dual-zone feature, where the rear speakers play from a different source, in their own "zone". The rear speakers can be playing something from your jump drive while the front speakers are listening to an IPod, satellite radio, a phone call, or, if you care to listen to the museum of broadcasting, terrestrial AM\FM radio and its polished turd, HD radio.

FOOTNOTE: The guy at the stereo shop was wrong, obviously, by saying that Pam's car was a 4-JBL speaker system. I knew that when he told me that I had a 4-speaker setup if those (yellow-circled port above) were the only plugs I had going to the factory unit. Luckily, I had already taken apart Pam's dash before going into this store, seeking a part and advice. That's how I knew for sure that I didn't have to purchase the $110.00 device.

I listened to each of her 6 speakers, all responding in beautiful clarity.