Rx400h Gauge Cluster Project *pics*

[cduluk]

Hey guys!! :)

As some of you may already know, I’ve worked on a few “personalized” projects in my Rx400h, most of which cosmetic. Most of my projects deal with the modification of interior parts, such as steering wheel, accent light, and wood additions. I figure, you spend most of the time behind the wheel, so everything in front of you should look as nice as it could be. <_<

I’ve already converted the steering wheel in my rx400h to the one used in the 06-07 GS models, and already finished a complete wood interior overhaul, converting the factory wood color to that of a dark maroon shade, as seen in the 02-04 ES models.

But there was still one more thing bothering me about the dash of the Rx400h, the fact that the illuminated portions of the gauge cluster needles (for the power meter, speedometer, fuel and engine temp meters) did not extend the full length, from fulcrum to the tip. You’ll notice that the factory needles' illuminated portion begins about 5mm away from the center of the gauge, rather than starting from the ACTUAL center to the tip.

Let’s start with some background.

If you look at the gauge clusters in some of the other Lexus models, you’ll notice that their needles begin illuminating at the very center (fulcrum) of the needle, and extend to the tip. This style of needles was first introduced in the 1990 LS400, which is often referred to as the “light-saber” needle design.

These needles were the first in any car to be illuminated “separately” from the rest of the gauge lights, by using a miniature CCFL in the needle itself (and LED’s in later generations). This is what made it possible for the needles light to begin at the very center of the needle. In every other design of needles (ones requiring light from beneath the cluster), no light can be formed at the very tip, since AT that very tip, there is a metal pin (which connects the needle motor to the needle) and light cannot pass through it. <_<

But even though these newly designed LS needles were appealing to the eyes, they were very expensive - not just to build, but to make them work. Since these needles use their own light source, it meant that electricity would need to be sent into the head of the needle. This required an even MORE expensive miniature “clockspring” device around the needle pin. Lexus did try to cut costs by using SMD/LED’s in the needles (as opposed to a CCFL) for the 92-96 ES and SC models, but it proved to be even MORE expensive when they began to burn out due to overheating.

I believe this is why the technology is only today used in the higher-end Lexus models (such as in the LS and LX)…and of course in the 06+ IS (because its added appeal is admired by the younger IS market). B)

At present, the ES, GS, RX and GX models still use the older technology of needles (requiring light from beneath the cluster) which limits the length of the needle. Inside these needles is a piece of clear plastic, which takes ambient light from beneath the cluster and throws it down the length of the needle. It’s the pin at the center of the needle that blocks light from going straight upwards, so Lexus just hid the first 5mm beginning at the tip with the needle cover.

Here’s one of the fuel or temp needles from the Rx400h cluster.

[cduluk]

When I first opened up the cluster and saw how these needles were designed, my first thought was that it would be impossible to get that extra 5mm of light. :( I also knew it would be impossible to just switch these needles with the types from the LS and IS, since they would require independent voltage, which would mean I’d have to add a clockspring unit- which is impossible to add to the Rx400h needle motors.

So I started to look for another way. I looked at pictures of gauge clusters from other makes and models to see if anyone else had figured out this dilemma. I studied various clusters that use the optitron technology (using high powered backlighting with a tinted plastic cover) just like Lexus does, and noticed something funny.

In clusters that use the old-fashioned needle technology like the Rx400h (using light from beneath the cluster) you will always notice a ring of light surrounding the needle head. This is light that escapes between the cluster face and the needle head.

In clusters that use the new technology like the LS and IS (making its own light in the needle head) this pattern of light around the head is not seen. Since the cluster and needle make their own light, there is no light going from the cluster and needle, so no light can escape. <_<

So I looked at all of the various makes and models with gauge cluster needles that were illuminated from the very center. All of them lacked the ‘ring’ around the needle head except one of them- The ‘04 Lincoln Navigator. :o

The needles of the Lincoln Navigator are illuminated from the very center, but still have that ring of light around the needle head. The overall shape of the needle resembled the ones used in the Rx400h as well, which also lead me to believe it might be of the same type. Either Ford was messy in sealing up the needle, or the needle must be illuminated from below. I had to find out. So I bought a used one for $20 on ebay and took it apart. :D

What I found was an exact replica of the technology used in the Rx400h needle, except the part of the needle that connected to the pin of the motor was separated from the clear plastic piece. You know how the first 5mm of the plastic piece in the Rx400h needle could not be painted white because of the needle pin connector? Well, the Navigator needle plastic piece is painted the entire length, with the pin connector attached to a separate black plastic film below the clear piece. This way, light enters, and can be reflected in the area over the pin, allowing the entire length from the center to the tip to be illuminated. GENIOUS!!!!! :D

So I purchased a used Rx400h gauge cluster on ebay ($150), took it apart, removed the needles, and modified them to mimic the Navigator needles.

I cut off the plastic pin connectors from each needles’ internals. I then sanded the entire bottom of the plastic pieces, polished them, and then re-painted them, adding the 5mm that was covered by the pin connector. Then out of thin plastic, I made a piece to mimic the new lower film used in the Navigator needles and glued the pin connector to it. I know you probably have no idea what I’m talking about… I just can’t explain it. <_<

I did a quick 5min demo using the clear internals from my old rx300 needle (same type as in Rx400h) and took pics. You’ll get the idea…

So after I finished modifying all of the needles’ clear plastic internals, I started modifying the needles’ black covers. I just cut out the 5mm using a razor blade, sanded it smooth, and painted them with Krylon’s flat black spraypaint, using a “mist” powder coat (to match the Rx400h gauge face texture). :D

I put the needles back together and installed them back on the cluster pins. I made a note of where the needles’ min and max points were before removing them so I would be able to put them back correctly without having to do calibration. <_<

So that’s about it! :D

[cduluk]

Here’s the stock Rx400h cluster (...well, Rx330/350, but they use the same needles)

See how the needles don’t light up from the center?

Here’s the factory Rx400h cluster w/o the tinting film.

[cduluk]

And here are the results after the modifications :D

[cduluk]

And with the flash to show the needles better <_<

I know this may seem like a minor detail to most (which it is…) but I figured it could be an easy and fun challenge. Out of all the Rx400h’s out there, mine’s got the longest gauge cluster needles! It’s just a little subtlety that can separate mine from the rest… :)

I’d love to have the engineers from Lexus examine my cluster and try to figure out what I did. Congrats to the engineers over at Ford though, who figured out the cheapest and easiest way to get the needles to start from the true center. There’s nothing like watching the gauges start-up and having the needles swing to their positions from the actual center, it just looks a lot better. Eventually i'll do the modification to my actual cluster (because it has my actual mileage) and i'll be able to sell this one on eBay to someone else... It's a lot of work, but well worth it. <_<

So enjoy and please comment! :D

[SW03ES]

The only issue now is that you have the secondary cluster in your car...accumulating mileage... and now the mileage in your original cluster will always be wrong...even if you reinstall it sometime down the road. So should you ever have to sell the vehicle you will have to disclose that the mileage displayed is not accurate.

I can appreciate the work...and the effort and I too like the needles illuminating all the way from the center like in the LS, but its absolutely not worth placing the stigma on the car of not having an accurate mileage readout. That might even make the car unsellable...

You couldn't install these needles on your cluster?

[cduluk]

Yeah!!! i could install the needles on my own cluster, good point. <_< I'll do that today, this way i can take my time working on the spares.

[lemon]

Dude, did you ever think of trying to solve poverty, or creating world peace or something....

That's a lot of work for 5mm of light...you must be OCD...?

Looks good, though. So far I like your steering wheel mod the best.

[SW03ES]

Yeah swap the needles into your cluster real quick before you drive anywhere so the mileage remains accurate. Be careful with the connectors...

OCD+lots of time+unlimited funds is a dangerous combination lemon LOL