Well you say you have a factory changer---more than likely this is a good thing. My best sugestion is to try to mod the changer cable for you factory changer to allow for an aux input. Most cd changers (w the exception of fiber optic Mercedes units) use a standard low lever output....thing of it as an rca output. On lets say an 8 pin changer cable three of your 8 pins are going to be left audio out, right audio out and common ground----the others are going to be power, ground, control wire etc. The tough part of your install is going to be finding out what three wires are your audio signal wires---these though usually stand out as a shielded set of wires. (theres enough different lexus forums that identifying the wires should be easy--someone can probably give you exact color and pin combos) The mod requires three relays. One relay for the left signal, one for the common ground and one for the right audio. Once you identify your three wires you will need to cut all three in half. What you are going to do is wire the relays so that 85 is ground, 86 is 12volts wired up to a toggle switch (to switch from cd to aux in) For each wire (left, right, signal ground) you are going to wire the wire going to the input of the factory headunit to 30 (remember one relay for each of the three wires) The output wires from the factory changer will go to 87a , and the output wires from your sirius device (rca output) will go be wired to 87. (I may have 87 and 87a backwards..its late ) To put this into perspective here is how its going to work. In order to listen to whatever is on your aux input device you will have to be in the cd changer mode. When your switch is off the relays will act as a pass through and you will hear the cd changer like normal...when you want to listen to sirius flip the switch and the relays will interupt the signal from the changer and then input the output of your sirius device to the factory radio-----the cd will continue to play and it will display as so on the factory radio but instead of hearing your changer you will hear the aux unit. Key factor is that you will have to be in cdchanger mode------I have not personally done this in a lexus to see if it will work..but it works fine on gms w/ seperate tape/cd player and in theory should work on any unit with a seperate changer or tape player. Let me know if you have any questions and sorry about the long post.

Originally posted by engin_ear
From reading this, you might be able to get it to work. It's cumbersome, and I don't like the use of a standard automotive relay for the application because of the lack of shielding, but that's just me.

As stated, you need to figure out which wires are the preamp output wires of the changer.

I would also verify that the CD preamp signal level coming out of the changer is a standard level before you start chopping,

Originally posted by Blanco

Assuming I find the right leads, why wouldn't they be standard line levels???
** Because factory stuff often uses strange levels, since they don't have to worry about compatibility issues with tons of other equipment.

Ok so under the assumption of standard line level signals, I'd cut the wires (2 I'm assuming) connect the changer side to say input A on the aux input switcher, and the sirius rca inputs on the B side, then connect the wires from the HU to the output side of the aux input switch, yes??

**Yes.

Now the Kenwood H2A runs off a 12V supply, could I just tap the CD changer supply to power the H2A?? BTW, did you get a chance to see the link I posted for the premade product I found?? If so do you think it'll work?? Never heard of a Molex connector. The reason I'm interested in the Pioneer, is that I"ve got a 98 GS w/nav, and I REALLY DON"T want to use the tape player for the input!!!

** Can't speak for how much current the H2A requires. I would leave the CD power leads alone (keep them clean and don't inject any noise form the H2A), and find another place to tap off power. As far as the Molex conn, if it is a factory mating type, you need to make sure it mates with Lexus. If it is the screw type, then you just cut and strip wires, slip into holes, then tighten screws on top, easy.