Please help me to identify the best one 12v constant accessory wire in order to connect Satellite radio and GPS. Please advise which one is the good one to tap (is this ignition one?). If you have pics I would really appreciate it.

Thank you!

I sort of hardwired wired my portable GPS into the cable leading to the accessory outlet on my 00 LS, details here: http://us.lexusownersclub.com/forums/index...si&img=1349

However, if I had known about "add-a-curcuit" connectors (sometimes called piggy-back fuses), I would definitely have used one instead. They plug into the under-dash fuse box and are perfect for powering accessories -- available on-line or at auto parts stores. Photo attached.

Thank you for your reply. Piggy-back fuses should be a good option but if you plug the fuse with 2 wires how to determine + (positive) and - (negative) ends or how to connect them to the radio ? Thank you!

A piggyback / add-a-curcuit fuse device plugged into the fuse box only provides the 12V current (positive). You could attach the ground wire from your electronic devices to any convenient ground on the car.

Here is a example on another forum of how someone attached the ground wire to a bolt: http://forums.s2kca.com/showthread.php?t=16128

Thank you! I got it now!!!

One more question please: does the 2003 GX470 OEM Radio has the AUX IN jack? I can't find it on the back of the radio.
I've connected satellite radio by now through the FM relay. Please advise. Thanks!

I don't think any Lexus cars had an AUX jack until about the 2007 model year. The following company is probably the most popular seller of input adapters for Lexus vehicles and it looks like they have products for the 03 GX: http://www.vaistech.com/

That add a circuit is exactly what I have been looking for!

Thanks Jim!