Remove Old Phone Installation From Ls400

[baldeagle100]

I have a 1995 LS 400 with a phone installation. I have discovered that the integrated phone is interfering with the operation of the speakers in the car. It gives me the impression that this phone would shut off the radio feed to the speakers when the phone was answered. Since the phone went with the previous owner and the setup remained with the car, I am stuck with it. I believe that complete removal of the phone setup will stop the "wauping" that is coming out of the speakers. I can hear the station I am tuned to in between the noise and if I hit the passenger side of the center cover(over the transmission) enough times the noise will stop occasionally and for a while I can listen to the radio. The reason I hit that spot is that the hanger for the phone was mounted there and I discovered this routing quite by accident when cleaning the carpet up the side of the center console. Ok guys, anyone know what to do??????

[RDM]

Does it appear to be OEM, or aftermarket? The OE phone transceiver is located in the trunk, you can just unplug it and remove it. Aftermarket, trace the wiring from the cradle to where ever the transceiver is and remove anything associated.

[baldeagle100]

Will do, thanks

[1990LS400]

Will do, thanks

If your phone system is a dealer installed Lexus phone system, on some of these it is important to plug connectors together after unplugging the connectors from the phone ECU in the trunk. I don't know if this applies to the 95-97 LS phone system but it definitely applies to the 98-00 LS.

If it is a Lexus phone system, it is a good idea to remove the vent you see when the armrest is open and unplug the handset cradle connectors. Do not cut wires! Always unplug the connectors. If you have a steering wheel phone command module, there is no need to remove it.

[Seguinite]

Will do, thanks

If your phone system is a dealer installed Lexus phone system, on some of these it is important to plug connectors together after unplugging the connectors from the phone ECU in the trunk. I don't know if this applies to the 95-97 LS phone system but it definitely applies to the 98-00 LS.

If it is a Lexus phone system, it is a good idea to remove the vent you see when the armrest is open and unplug the handset cradle connectors. Do not cut wires! Always unplug the connectors. If you have a steering wheel phone command module, there is no need to remove it.

[Seguinite]

Thanks for the original question, Bald Eagle, and thanks to 1990LS400 for the tip NOT to cut the wires. A red light runner totaled my "old" 99 LS 400 after 300K near-perfect miles. Thankfully, no one was hurt. After wiping away the tears, I bought a direct replacement (cherry, with 200K fewer miles) but it came with an old built-in phone. I was working my way through its removal and was about to cut the wires "upstream" from the plug connectors when I decided to check this forum. Because the phone is integrated with the audio system, it makes sense that cutting the wires could disable or screw up the performance of the radio.

[1990LS400]

Thanks for the original question, Bald Eagle, and thanks to 1990LS400 for the tip NOT to cut the wires. A red light runner totaled my "old" 99 LS 400 after 300K near-perfect miles. Thankfully, no one was hurt. After wiping away the tears, I bought a direct replacement (cherry, with 200K fewer miles) but it came with an old built-in phone. I was working my way through its removal and was about to cut the wires "upstream" from the plug connectors when I decided to check this forum. Because the phone is integrated with the audio system, it makes sense that cutting the wires could disable or screw up the performance of the radio.

Your Lexus phone system is also attached to the HVAC system. When a phone call is received or made, the fan speed is reduced. Sometimes with the trunk mounted phone ECU fails, the radio will go into permanent mute mode and the HVAC fan speed will default to Low. On your 99 LS, it is important that you plug the two large male and female connectors together after unplugging them from the phone ECU in the trunk.

A friend's 99 LS Nakamichi went into mute mode last year and he assumed that his radio or amp was bad due to a burning smell in the car interior. He even bought used replacement Nakamichi components. On a whim, I unplugged all the connectors from his phone ECU, plugged the two large ones together and - voilà - his radio worked again after months of silence.

After removing or unplugging the ECU in the trunk, if you want to get the cables out of the way and away from potential moisture, there may be a plastic bracket on the bottom of the plastic tool kit receptacle housing for that purpose unless the phone installer removed the bracket - see attached photo.

While you are unplugging your phone components, note that the center front pin in the phone connector under the console air vent on the drivers side is a mute pin. If you want to install an aftermarket Bluetooth phone kit, plugging the phone kit's mute wire into the connector to contact the mute pin (secure it with a cable tie) will mute your radio when a phone call is in progress but will not lower the HVAC fan speed. The antenna coax cable that is also under the armrest vent leads to the phone ECU in the trunk.

If you have an aftermarket phone charging cradle with an antenna connection, you can use the rear window imprinted antenna by connecting your charging cradle's antenna connection to the coax cable under the armrest and by connecting the two coax cables in the trunk together to complete the circuit. Connecting the two coax cables in the trunk requires an adapter - I bought one at Radio Shack.

[Af TWITCH]

Does anyone have any pics of the phone ecu in its original location? My radio is muted so I have no sound but keep hearing about the phone ecu but can't seem to find any good material on it. Thank you 95 Ls400

[1990LS400]

21 hours ago, Af TWITCH said:

Does anyone have any pics of the phone ecu in its original location? My radio is muted so I have no sound but keep hearing about the phone ecu but can't seem to find any good material on it. Thank you 95 Ls400

This photo is of a phone system ECU in a 1998-2000 LS400 but I think the one in the 95 LS400 looks about the same.  It's under the false floor on the right side of the trunk.