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Installing A Handsfree Phone Car Kit

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Rather than continue the multipage "Integrated Phone" topic of the past, I thought it better to start another topic.

No, I still do not know how to make the steering wheel phone control work for a non-Lexus phone or how to play the audio for the phone call through the Lexus audio system without using a mute lead from one of the U.K. or European companies that sell them.

However, I am very happy to report success in connecting the mute wire of my Nokia CARK-91H car phone kit to the Lexus phone wiring harness on my 2000 LS so that the radio/CD/Cassette automatically mutes when a call is placed or received. Accomplishing this task is quite a relief because I have missed important incoming calls after switching to a Nokia 6340i phone with a lower ring volume. After spending so much time and energy learning about phones and car wiring, it is ironic that connecting the Nokia mute wire to the LS400 phone harness required no wire splicing, no relays, and no new hardware.

I simply ran the Nokia yellow mute wire to the male phone connector on the driver's side below the vent cover at the rear of the console, stripped 1/4 inch of insullation from the wire, and jammed the wire into the center front terminal of the connector. I then secured the wire with a wire tie. Before inserting the wire, I verified that this terminal muted the audio system by probing it with a grounded automotive test light. On the 2000 LS, there is an additional mute point in the male connector attached to the bottom of the tool box housing in the trunk - the wire color is "grey with green stripe" - I verified its function by probing with a grounded test light to mute the audio system.

Unfortunately, it seems that Lexus changes wire colors and locations on a seemingly random basis. Although not an electrician, I've been told that it is unlikely that one will do damage by probing connector terminals with a grounded test light - as long as one does not bridge multiple terminals with the probe. So, if you have or plan to get a phone car kit with a mute connection, you may well be able to find a mute point on an LS400 or other model Lexus of a different year. I do know that the mute wire for a 2001 RX300 is the purple wire in the telephone connector in the trunk. I've ran into a couple of people who have connected their phone's car kit mute wire to the Lexus Link mute point on LS430's.

Attached is an impromptu "how-to" manual with photos of the mute wire connection.

Please respond PM me if you have comments, suggestions or want me to try to help.




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What a great effort and one that I think will be much appreciated by many in the future. Keep up the good work!! I would just like to add a word of warning in response to the following.

I verified that this terminal muted the audio system by probing it with a grounded automotive test light

A voltmeter should be used when testing wiring harnesses rather than a 12V test light. Many electrical circuits in cars today have very low operating currents and the current draw from a test light can be enough to cause thousands of dollars worth of repairs.


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Thanks for straightening me out about using a voltmeter instead of a test light. I'm mostly clueless about electricity - a sorry situation for the son of an electrical utility company superintendant.

I will put your caution in my documentation.




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