I found the noises to be coming from the centre console on the passenger side. I have not investigated the driver’s side where I believe there is another motor located.

Removing the Dash Trim

For the JZS171, accessing both the mode-select and speed-select motors is just a case of removing the glovebox.

The lower trim underneath the glovebox has 3 clips holding it in - just pull the trim off carefully and twist out the courtesy light bulb.

Next, open the glovebox and pry off the small rectangular panel in the topside left. There are yellow cables attached to this so just push it back through the hole and out of the way.

Now go ahead and remove 2 screws in each top corner of the glovebox.

Finally, there are 2 x M10 hex screws to remove in the lower corners of the glovebox.

The glovebox assembly has 3 clips holding it in - just pull away carefully. Be sure to disconnect the cable to the glovebox interior light once you can access it.

Improve Access to the Motors

These are the speed-select and mode-select motors (circled red):

To get better access to them, remove the screw securing the the white vent assembly. This will then pull away to reveal access to all of the motor’s retaining screws.

Removing the Motors

To make access easier to get at the top motor (the mode-select motor), move the cable cluster clipped onto the bracket nearby (circled red). You should now be able to get a hand onto the top motor’s connector to unplug it.

From this point, you can now unscrew both of the motors. You will need a short/stubby screwdriver to make things easier.

Repairing the Motors

Speed-select motor on the left. Mode-select motor on the right. Part numbers printed on the motors for reference.

There’s already good references both in forums and YouTube videos on why the motors malfunction so I’ll not repeat it - take a look at the references section at the end of this guide for more detail.

Speed-Select Motor

This motor for me was the main culprit for causing the chattering sound. The repeated back and forwards of the motor trying to align itself is the cause of the chatter. You can see the action in the following:

Speed select motor issue:

To fix, the motor casing needs to come apart but before doing this, mark the current location of the white plastic arm. Mark the casing with a pen and take photos - you’ll need these to refer to when putting it back together.

Take care with the next step - its very easy to snap the casing clips.
Using a small flat-bladed screwdriver or pry tool, go around the casing and loosen up the plastic clips located around the edge - there’s about 6 with a couple of smaller clips on the cable connector edges.
The case then splits in two.

To repair the chattering motor arm, you need to clean up the dirty grease on the cog - You only need to clean the grease from the area that is grooved by the contacts from the other side of the casing (circled in red).
The chattering occurs because the grease gets contaminated with metal on the resistance material and interferes with the potentiometer signal.

Using an alcohol cleaner or an electrical contact cleaner, clean away the contaminated grease. Best method is to dip a cotton bud in cleaner and then wipe the affected area carefully. Also do the same for the copper contacts on the other half of the casing.

Once the patch has been cleaned, using a fresh cotton bud, take some clean grease from elsewhere in the mechanism and re-coat the cleaned section.

The motor casings then need to be put back together whilst ensuring the arm is in the same place it was when you dismantled it.

Mode-Select Motor

The mode-select motor should be dismantled in the same way as the other motor. Make sure you mark the location of the arm and are careful when prying up the clips.

The mode-select motor operates in the same way as the speed-select motor so should be cleaned in the same way. Unfortunately the resistance material for the potentiometer (the large cog) is reversed. Using a cotton bud with cleaner you should again clean the grease but you will need some judgement as to where the affected area is as you cant necessarily see it.
I found bending the cotton bud into a 'U' shape made it easier to both clean and apply grease as I was able to hook up under the cog.
This job could be made easier if the motor arm could be removed - I investigated this but it appears to be glued in place or at least not meant to be touched.

I traced the grinding noise in this motor to the worm drive cog having too much play up and down the motor output shaft, causing it to spin freely without engaging. Here’s a video as its easier to show:

Mode select motor worm gear issue:

To fix this I did 2 things:

1. Super glued the worm drive cog in-place on the motor shaft, preventing it from sliding up.
   (I also super glued the same worm drive cog on the speed-select motor)
2. Glued in place a very thin piece of plastic between the worm drive cog and the motor casing to reduce the gap between them. If the worm drive ever comes un-stuck from the motor shaft, I have reduced the play in the cog which mean it continues to be engaged properly.

Installing the Motors

Replacing the motors back into the car is obviously reverse of removal.

The only thing you need to be aware of is ensuring the pins on the end of the motor arms are inserted into the vent mechanisms correctly. They should slot into the grooves to allow the vents to open/close.

References

Very in-depth writeup on Club Lexus: https://www.clublexus.com/forums/gs-2nd-gen-1998-2005/634751-how-to-fix-your-servo-motors-complete-guide.html?fbclid=IwAR05NIwXHdW7xs4XfH2NQRDT14WMZ2qSOe1QeOVFOstQLZgi2Hb1xFzUUqA

Explanation on why the motors go bad and how to fix them: https://www.clublexus.com/forums/gs-2nd-gen-1998-2005/501372-diy-repairing-air-mix-servomotors.html

Being JDM the factory stereo only receives 70-90 Mhz FM radio. It also has a 6-disc CD changer and a cassette deck and I can't remember the last time I used either of those.

Audio Upgrade Options

Options for upgrades as far as I can tell:

• A radio band expander to increase the range of FM frequency the radio can receive.
• A BeatSonic unit to allow continued use of the on-screen air con controls and an aftermarket head unit to replace the CD disc changer.
• Manually figuring out how to keep the air con controls and wire in another head unit.
• Using the factory TV receiver to allow an external AV-in source.

Long-term, I'll look to upgrade to an aftermarket head unit using a BeatSonic device and harness as this is as plug and play as possible with a JZS171 but for now, the simplest method to have music in the car is to use the factory TV tuner AV-in.

Equipment Needed

The factory TV tuner in the JZS171 wagon lives in the boot on the driver's side, underneath the carpet and storage trays. You will need to remove 2 x 10mm nuts to get the tray out and access the tuner.

The blue connector on the tuner is an AV input. I'm not certain what the factory wire is connected to here - I assume its providing an input for a DVD player or similar? This socket will give us a way to feed both audio and video to the factory car stereo.

To make use of the AV-in, we need a 'VTR cable'. This is simply a cable with the correct 6-pin blue socket at one end and 3 RCA inputs (red/white/yellow) at the other.

There are a 2 different types of VTR cable available for the Toyota Crown. They are both 6-pin blue connectors but one is square (like the picture above) and the other is flat. The square is typically needed for series 2 model Crown and the flat is series 1.

I pretty much only listen to music via my phone or the internet these days so I decided to add a bluetooth receiver to this setup so that I could pair my phone to the receiver and stream music to the car stereo. The receiver I used is a basic bluetooth receiver purchased from eBay and has 2 RCA (left and right) outputs. It operates at 12 volts.

Installation

• Locate the TV tuner in the boot under the driver's side storage tray. 2 x 10mm nuts secure the tray.
• Unplug the blue connector from the TV tuner.
• Plug in the VTR cable into the now empty blue socket, on the TV tuner.

• Connect the BT receiver's red and white phono male plugs to the corresponding female plugs on the VTR cable.
• Connect the ground wire (black) of the BT receiver to a metal ground point in the boot. Adding a ring connector to the wire and fastening under an existing nut/bolt in the boot is the most straightforward option. I choose the nut that secures the TV tuner unit to the boot floor.

• Connect the live wire (red) of the BT receiver to a 12v source, preferably switched so as not to drain the car battery battery when not in use.
• I have made use of an existing 10amp fused connection I created when installing rear fog lights. I needed to run a new wire to the front of the car, along the driver's side interior trim to the fuse. This connection is fed from a 12v source that is live only after the ignition is switched to key position 1 (ACC).
• The interior trim comes away easily as is clipped in along the door edges.

Setting up the Stereo

To have the VTR cable's inputs played through the car's stereo, you must enable the 'VIDEO' function within the radio player. This option is not present on the touchscreen until a device is connected to the TV tuner blue socket.

Once powered, the BT receiver should be visible to mobile phones for pairing. I found that it wouldn't pair correctly unless the engine was running - I guess there wasn't quite enough voltage with just the ignition in position 1?

I've setup my phone to auto-switch to Android Auto when the Crown's BT receiver is detected. This means my music will start playing where it last left off and the phone will go into driving mode for maps etc. [EDIT: This festure is no longer supported on Android out of the box]

Of course, with the VTR cable, you can go ahead and connect any device that outputs audio or video to the Crown's speakers or screen; games console, UK TV tuner, DVD player, etc.

As standard, the rear lights operate as follows:

• All 4 on each side light up together when the sidelights or headlights are switch on.
• The top 2 bulbs on each side light up the 2nd filament when the brake pedal is pressed.
• The bottom row of bulbs on each side do not have an active switch for the 2nd filament - assume these are reserved for the rear fog option with the factory-extra "Winter Comfort" pack.

I have used the outer lower bulbs as fog lights. The 2nd filament is the fog, whilst the primary filament is the rear running light.

(I wanted to use the inner-most bulbs but that would mean more work running wires through more interior trim pieces and that is too much like hard work right now)

The hardest part about the whole process was removing and replacing the light clusters from the car body as the space is VERY tight to get your hands in. You need slender fingers, a small 10mm socket and ideally a 10mm spanner with a flexible ratchet head just to make things a little easier.
You will drop the nuts when doing this but they typically tend to fall through to the boot floor so can be retrieved without too much issue.

Wiring the Bulbs

Remove the light cluster from the car body:

• 1x 10mm nut securing the lower trim piece below the light cluster. The trim clicks into place with a fastener on one side but may need hep by wedging with a plastic tool (so you don't scratch the bodywork).
  You must remove this piece before you can remove the light cluster fully.
• 3x 10mm nuts holding the unit to the car. 2 are easy to get to but the 3rd is practically inaccessible. Loosen it with a small 10mm spanner and then undo it with your fingertips (I have delicate IT geek fingers and could only just get a touch on it). You may be able to fish it out by hand but if you drop it, it should be retrievable from the boot floor.

Once removed, disassemble the light cluster so you can get to the lower bulb and the look connecting to it.

Strip back the sheath on the wire of the lower bulb holder and save for later. This was white on the passenger side and black on the driver's side for some reason - not sure if relevant.

With the wires uncovered I found that the 2nd filament wire (GREEN + WHITE stripe) was not connected to any source. The wire was taped up in the loom. This was the same on both sides of the car.
Really handy though as Toyota have left me a wire to connect my fog light live wire to!

For reference, the wire colours are as follows:

• Solid GREEN = live for running lights - the primary filament
• GREEN with WHITE STRIPE = live for 2nd filament
• WHITE with BLACK STRIPE = earth

I removed the black tape and crimped a spade connector to the GREEN + WHITE STRIPE wire - this will be the live for the fog light fog.

The bulb is already earthed so no need to wire anything for that.

It's a good idea at this point before refitting the light cluster to replace all the bulbs as they're tricky to get to when it's all back in the car. I also didn't refit anything until the complete circuit was made up and tested, just in case there were issues that needed troubleshooting.

Wiring the Switch

To pass an MOT in the UK, the switch for the fog lights has to be mounted on the dashboard where the driver can reach and see it during driving and it must be illuminated to show the fog lights are on (or have a bulb in the dash cluster).

3-pin illuminated rocker switches are dirt-cheap and don't take up much space so ideal for quick MOT fixes.
These switches need a positive voltage source and an earth. The 3rd pin is the source for the fog light bulb.

For the positive, I used a multi-meter to probe the wires from the ignition barrel to find a 12v source that was live only once the ignition was on - this was so I could ensure I wasn't  going to connect to a permanent live feed and risk creating a drain on the battery.

I got lucky here as my Crown has an aftermarket remote engine start module which has been spliced into the ignition circuit using a harness to interrupt the factory wiring. I've used this to link into so I don't damage any Toyota factory wiring.
The wire I used was blue in this instance but the pin is the far left in the ignition barrel connector. This wire supplies 12v on the first click when you turn the key (position ACC).

For good measure, this positive source also has an inline 10amp fuse in place.

For the earth, I've run a wire from a mounting nut/bolt under the dash that is part of the metal bodywork.

There are no switch blanks in the crown to modify to fit the small rocker switch unfortunately so I have installed it directly into the dash on the same piece of trim that the wing mirror controls and ignition key are located.

Incidentally, this is the exact location of the rear fog light switch from the "winter comfort" factory option and as such, the dash piece has the moulding on the rear for the fitting of the Toyota switch.
I've drilled out this hole and used a dremel to further widen to fit the circular shape of the rocker switch.
You can see in this picture how the rocker switch (the 3 pins) fits snugly into the existing hole where Toyota switch would go (if it had been specced from new).

All that's left is to run a single long wire from under the dash, along the driver's side floor (tucking under trim pieces), through and behind the rear seats to the rear light cluster. Here I split the wire off and ran it along the rear of the boot space to the passenger-side light cluster so both bulbs could be activated from the same switch/wire. Terminated with spade connectors they were tucked under trim and connected to the refitted light clusters/bulbs.

The 3 wires can be fed up through the dash to the opening near the ignition and connected to the rocker switch. The live for the fog light bulb is the middle pin.

When the switch is thrown, the 2nd filament in the lower outer bulbs of the rear light cluster is switched on and the rocker switch in the dash has an LED to show the circuit is active.