franklinhu

My 2000 LX470 had a problem where an annoying alert tone (eeeeeeeeeee....) would turn on after about 5 seconds of turning the key to the on position. I think it is the seat belt warning chime. It would not turn off, ever. Lexus published a service note indicating that the junction box to the left of the driver seat needed to be replaced and the dealer wanted $1500 to do that.

Well, I just wanted to kill the thing that was making the alert tone but no one would do that, so I did it myself. It isn't that hard, you need to remove the instrument panel. This is done by just pulling out the black plastic piece below the instrument panel (it isn't screwed in). Unscrew the screw at the bottom of the steering column. Then turn the steering wheel to the left until you can see the screw hidden by the wheel and remove it. Turn the wheel right and repeat. You can then pull off the upper/lower plastic panels covering the steering wheel. There are 2 small screws on the left/right of the instrument panel and 2 on the top of the panel. Remove those. Then there are 2 large bolts holding the electrical connections. Unscrew those, but they do not come out. You can then tip the instrument panel forward and out. Pull the steering column up and as far down as possible and you should be able to barely maneuver the instrument cluster out.

After that, just take out all the screws holding down the outer cover. You will see a circuit board and on the left, you will see 2 circular boxes with holes in the top. The small one on the left is the chime making the annoying noise. To silence it, I put a small screw into the hole until it reached the piezo element to stop it from vibrating. After doing that, it still makes a barely audible tone, so I know I didn't mess up anything else and I didn't have to destroy anything and it is reversible if necessary.

It is a bit of a trick to get the panel back into the dash. After you get it positioned, you have to get the electrical connections back on. I did this by running my hand underneath the right hand and guiding the electrical connection so that it is close. Once it is close, you can try screwing the large bolt and this captures the electrical connectors and brings them together. The left side is a bit trickier since there is less room to put your hand under, so you just might try lining it up and pushing back on the panel. If you're lucky you can turn the screw and it will capture the connector. It's not easy, but it can be done with some patience.

Now it seems silly to spend $1500 to replace parts when a simpler fix is at hand. It seems the answer to any problems like these is to just replace everything for thousands of dollars - even stuff like a bulb on the instrument panel. Lexus doesn't publish any information on the circuit boards for the instrument panels - it's a black box as far as servicing is concerned and I don't see why it should be. But if you do decide to fix it yourself, remember that you do so at your own risk and that me or anyone on this forum is not liable for any damage you do to your car or yourself.

V8_Fan

I thought there was a TSB or recall on the junction box on the 2000's. The culprit was metal shavings in the box. The solution is to vacuum or blast it out w/ compressed air...would have saved 'ya a lot of effort.

franklinhu

Yes, there was a TSB on that problem, and I had previously tried blowing out the junction box without removing it. However, looking at the junction box, it appears to be almost impossible to remove as the screws appear to be inaccessible and is tied down to various other components. Nothing in the online Toyota service manual told me how the remove the junction box and it appeared impossible to do so, so removing the instrument panel appeared to be the easier way to go. Also, after a while, whatever was making the alarm go on has now gone away on its own since I cannot even hear the tiny sound that the alarm used to make.