How to Disassemble the Instrument Cluster
1990-1992 Lexus LS400
Important: 90-92 instrument clusters and NOT the same as 93-94 clusters! I have been saying this for a long time on the forums but it seems people still don't get it. You can check a parts manual to verify if you don't believe me. Yes, they look VERY similar but they are NOT the same. The procedure shown here is similar for 93-94 clusters as well but somethings will be different.
This is a gateway tutorial that leads to other procedures. Maybe you need to replace a light bulb that burned out, maybe you want to change lighting colors, or maybe you need to fix slow working needles. Whatever the case may be, you will need to disassemble some, or all of the cluster. The speedometer and tachometer in the cluster are lit by cold cathode tubes. The remaining gauges and indicators in the cluster are lit by traditional incandescent bulbs. All these bulbs are clear and shine through colored plastic pieces to give you the whites, greens, blues, etc. The stock bulbs are great but they don't last forever. What's great is that you can replace most of them with longer lasting LED's. Anyway, in order to change these you need to disassemble the cluster, here's how you do it...
- 12 volt plug in adaptor or 12 volt car battery
1) Remove the instrument cluster from your car. Make sure your battery is disconnected before you remove the cluster or the air bag light will be on when you put everything back together and start the car. If you forget see this tutorial on how to turn the air bag light off.
2) You can test the cluster on your workbench by connecting wires from a 12 volt source to the terminals shown in this pic. This is important because you want to easily test any changes you've made. Throughout this tutorial you will want to discharge any static electricity you've built up by touching something metal, these parts can be delicate.
2b) I used small clamps connected to the wires to keep them on the terminals. Don't mind the wire colors, that's what I had!
3) Place the cluster on something soft like a towel and remove the 8 screws and 2 plastic covers, set covers aside.
4) Disconnect these 2 connectors on the power source unit (the part with the silver cover).
5) Disconnect the remaining 3 connectors on the power source unit and set it aside.
With the power source unit removed you can replace the indicator bulbs now if desired. The circuit board has labels by each bulb for its function, otherwise they are the blue pieces in the picture. They can be removed by twisting them out, counter-clockwise if I remember correctly. If you just want to replace a burnt out bulb with another incandescent bulb you can pull the bulb out of the blue socket and bring it to your local auto parts store to find a match. If you want to replace the bulb(s) with LED's then see changing cluster colors. The number of bulbs will depend on what features your LS has (ex. trac, air ride).
6) Flip the cluster over and remove the 3 screws for the tinted cover. Now gently push the locking tabs around the cover down and remove the cover. This may be tricky so take your time and don't break the tabs or tinted cover.
7) On each side of the cluster, disconnect 1 connector and remove the 5 highlighted screws.
8) Hold both the main cluster assembly (white part) and the lens/needle plate and flip the cluster back over. Now, carefully pull the lens/needle plate off the main cluster assembly and set it aside. At this point you can remove the needles from the lens if desired; they are extremely delicate so be careful. Before doing so make a note or take a picture of where your needles are positioned. The tach and speedo should be resting at 0 and the fuel and temp gauges will vary. To reposition them just move it up or down with your finger, but do not rotate them a full 360 degrees. The fuel and temp needles slide out to the side, the tach and speedo have two screws each that need to be removed then you can slide them out by holding the needle horizontal and using a twisting motion.
9) Remove the 6 screws and then you can remove the 2 cold cathode tubes.
10) The last main thing remaining is the circuit plate on the back, this can be removed with 3 screws. The odometer can also be removed but you can probably remove that at an earlier stage if that's what you're going for. The trip meter can also be removed.
11) Do what you need to do on the cluster now. Install is reverse of removal.
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