scubadogg

First let me thank all the others that have posted information on the other platforms; the GS300, and IS250 Forums in particular has lots of info on the Gen 5 Nav systems that made my work a lot easier.

Second you can do this your self, no need to spend the money on some of the commercial devices. All you need is simple tools, a magnetic screwdriver, socket set, wire cutters, small wire caps and/or tape, and a simple switch. Also some kind of plastic trim removal tool or a taped screwdriver is required. I purchased a package set of five tools from Harbor Freight for about $5 or so. IMHO the hardest part is taking care of the trim removal and running a wire to the cabin. Just take your time and you won’t damage anything. Also be careful not to lose the 9 or so screws you need to remove, they can fall in places you wont be able to recover them. I stuffed the openings with towels and used a magnetic screwdriver while removing the screws. Also if you plan to add a Vaistech MP3/Video interface SL2Vi or SL2Vu this is the perfect time to do this in conjunction with the NAV hack.

So here is what I am going to present, I will give you an overview of the Mod, I will present the effected wiring, and then follow up with some details, photos and some technical information.


Mod Overview:

References: I won’t go in too much of the technical details of the why’s this work; as there is a wealth of info in other ClubLex Forums posts. Another valuable source of information is the Online Toyota Technical Information Database, https://techinfo.toyota.com/ Lots of good information there, but it can be difficult to navigate the site. You can download most things in pdf format. For $15 you get 48 hours of continuous access, which I used to download almost everything I could find on my 2005 LS430. You will find information on parts remove/replace, diagrams, parts lists, connector/wire information, service bulletins, etc, etc. I am reluctant to post most files do to copyright issues.

Technical Summary: You need to ground the Parking Brake signal coming into the NAV MDU (Multi Display Unit). You need to cut/disable the VSS (Vehicle Speed Sensor) coming into the NAV MDU. If you do just these two things you will be able to access locked Bluetooth functions while driving, and if you install a Vaistech video interface you can watch video while moving. In order to allow Nav Destination input while driving you need to route the VSS signal on the NAV EU (Electronics Unit) thru a switch you install in the cabin. Alternatively you can just cut that wire, but navigation will be jumpy (not recommended).
Locations: The Nav MDU is of course located in the center console. The Nav EU is located in the truck in the passenger rear wheel well and is easily accessible.

Basic Steps. Step One is cutting two wires on one harness of the NAV MDU. Connecting one of the wires to an electrical ground location and capping the remaining three connections. Step Two requires cutting one wire from the NAV EU and inserting a switch in-between those wires and locating that switch in the cabin. Below is the

Wiring Harnesses and Pin Locations

NAV MDU

M4 Connector (26 Pins)

(Facing the front of the NAV unit display it is the connector located on nearest the passenger side or right side)

(M4-16) LG Pin #16 Light Green wire: Cut wire; GROUND the side that goes into the radio. Tape and/or Cap the other side

(M4-25) V-W Pin #25 Violet/White wire: Disconnect/Cut wires, cap/tape both sides of the wire.


NAV EU

N4 Connector (18 Pins)

(Looking down on the unit in the trunk it is the furthest most left connector or the connector facing closest to the passenger compartment)

(N4-5) V Pin #5 Violet wire: Cut wire; insert a standard switch SPST (Single Position Single Throw) that is cabin/driver/passenger assessable. Run a wire between switch in cabin and the NAV EU in the trunk.

(I would consider letting a professional car stereo installer run the wire from the cabin to the trunk, since you must remove a portion of the rear seat to get access to the trunk. I would think they would charge between 1 –2 hours of labor for that, <$100 I would think.)







Detailed Instructions:

For step one, you need to get access to the MAV MDU. There are various instructions on getting access to the NAV MDU on the LS430 Forum. See post “Service Manual: Removing Navigation Unit” For trim removal see this file on the Forum, (davegs4.pdf) at “04 LS430 Ashtray Alternative” post #69. It shows how to remove almost all the interior of a LS430. All this and more can be found at Toyota Information Service online.


NAV MDU: remove and unplug the switch assembly that has the seat heaters, etc with a trim removal tool. Now you have access to the three screws below the “ECT Switch assembly and others” remove them and move switch assembly out the way, you don’t have to unplug it. Remove the cover below and around the CD changer. You need to place the car’s stick shift in Drive in order to pull CD cover assembly out and turn it upside down so you can use it as a work holder for the NAV/Radio assembly you will remove next. Now you have access to the two lower bolts that hold the Nav/Radio Assembly, remove them. Next remove the two temperature control switches with a trim tool, they are in there good so some careful effort is needed to remove them. Remove and unplug the switches which will give you access to the four screws that hold the Nav /Radio Assembly at the top. Remove the 4 bolts using a combination socket set (10MM) and a magnetic screwdriver so the screws don’t fall into the abyss! Gentle wiggle/pull the whole assembly forward. Once the NAV Assembly is out you should be able to turn it sideways so you can work on the unit. There are two connectors at the top of the unit; I removed both connectors as it gave me more run to work. I used the CD cover assembly trim piece as a stand for the NAV Assembly so I could work, cover all with a towel etc to protect your trim! It’s a Lexus you want to keep it looking Sexy Lexy! Once you have access to the back of the NAV MDU, you will be working on the M4 connector, the 26-pin connector nearest the passenger side. Follow the instructions below.



NAV MDU

M4 Connector (26 Pins)
(Facing the front of the NAV unit it is the connector located on the NAV MDU nearest the passenger side or right side)

(M4-16) LG Pin #16 Light Green wire: Cut wire; GROUND the side that goes into the radio, use the bolt and a new wire as shown. Tape and/or Cap the other side.

(M4-25) V-W Pin #25 Violet/White wire: Cut wire, cap/tape both sides of the wire.



NAV EU: is located in trunk under the passenger side rear wheel well. Once you remove the corner trunk trim piece, you just remove the two bolts that hold the NAV EU in place. Because the NAV EU is on a rail, you need to move the unit up and forward to release it from its rail. Once you have the unit out of the rail. Remove the N4 connector and follow instructions below. Once you make the mod, don’t be alarmed that the NAV system will do a startup boot.

NAV EU
N4 Connector (18 Pins)
(Facing the front of the Nav EU it is the furthest most left connector)

(N4-5) V Pin #5 Violet wire: Cut wire; insert a standard switch SPST (Single Position Single Throw) that is cabin/driver/passenger assessable between the two wires.



References:

https://techinfo.toyota.com/ Toyota Technical Information

These are some of the documents there that where useful:

Lexus Navigation System: Terminals of the ECU (2005 LS 430)

Navigation ECU Replacement (2005 LS430)

Navigation MDU Replacement (2005 LS430)

Audio & Visual System Location

Overall EWD (Electrical Wiring Diagram)

Component Location

Glossary of Terms



That’s It I hope a few of you find this useful.

scubadogg

Here are some more photos to guide you

sparky3

So my question is this - for this violet wire that needs to be cut in the trunk and switched - does it already run up front to somewhere in the cabin? Wouldn't it be easier to splice it in the cabin somewhere so I don't have to take out the back seats?

Shawn

sparky3

Also, just to make clear - I'd have to run 2 separate wires back up from the trunk area, correct?

scubadogg

For the NAV EU, you need to clip the VSS wire which is the Violet wire. This will give you two wire ends. Now run enough two-conductor wire that will reach somewhere in the passenger compartment. Then tie/connect each of two ends of the cut VSS wire to sperate ends of the wire you ran to the passenger compartment and connect up to the switch. So now when the switch is closed, Nav system works as normal. When the switch is in the open position. You can input your destination then afterwards close the switch when done to return normal NAV operation.

sparky3

I understand that - my question is where does that violet/white wire come from that goes into the NAV EU? Are you sure there isn't a place that it can be clipped from inside the cabin so I don't have to remove my back seats?

LS430inDE.

Holy ****---amazing work...not only to DO it, but document it all!!!! Excellent excellent, excellent work dee-ohh-double G......dogg!!!!!

scubadogg

All VSS signals come from the combination meter (wiring hub), behind the instrutment panel, lots and lots of wiring, I'm sure you can get it there...good luck!

GS3Tek

iTrader: (8)

So AWESOME SCUBADOGG. Thanks for pointing the VSS wires

I was back there in the trunk last week fooling around with adding an RCA cable for the audio input.

any DIY is a pain and lengthy to document....sometimes it's even harder than the mod itself

scubadogg

thanks for the compliements, I just wanted to do my part for the Fourms, I found lots of great info here. Your right, doing the "write up", took more time than the mod.

StanVanDam

Great write-up. I should be receiving my SL2Vi on Monday and will be using this article. Is the Vehicle Speed Sensor wire in the same place for the 2002 LS430UL? Also, I'm curious as to where you placed the Vehicle Speed Sensor switch. Could you post a pic? Thanks!

toantran99

Anyone got this to work yet?

StanVanDam

My SL2Vi came in today, and I successfully installed it with my iPod Touch 3rd gen. However, I did not do the VSS bypass. The back of my Nav Screen is different from the instructions here. Does anyone know how to do the equivalent function on a 2002?

The 2 8mm bolts behind the passenger temperature setting buttons fall down into an irretrievable spot if dropped, so make sure you have lots of putty on your 8mm socket. I lost one of the bolts down there.

The 2 bolts on the driver side fall down to where the VSC panel is. Keeping a plastic bag in that area is a good idea, saved my first bolt that way before finding some poster putty.

sparky3

I will be doing this sometime soon.

AudioBuff

Scubadogg,

Where did you get that perfect-matching switch? I tried a number of websites and stores, but could not find anything other than black?

I will have my audio installer try and duplicate your suggestion regarding the NAV override.

Please let me know where I can get a switch like yours.

Thanks!!!