I have a 98 lx470 with the same tail light configuration as any other LX until the model year 2005. just as reference, i will give you the bulb numbers:
1.) 4 red bulbs (brake and tail light) are 7443
2.) turn signals and reverse bulbs are 7440
there is more than one way of going about this conversion. what i did was simply buy LED LIGHT TOWER bulbs from
http://autolumination.com/7443_7440.htm (scroll to middle of page).
now these bulbs lit up and turned off very rapidly, which is characteristic of all LED bulbs (light quicker and then turn off much quicker as well). im sure you've all noticed this difference when you see LED tail lights and stock tail lights. the only problem with this was that the bulbs were not nearly as bright as the stock bulbs. however, this is simply 'remove the old one and put in the new one" procedure.
a much better way to go about this is a little more involved. many people are able to make their own LED arrays; which are basically circuit boards soldered with the LEDs of their choice and resistors. if you cannot do this, you can also go to
www.ledcar.com and purchase their premade LED arrays. i highly recommend that you do so. another good option is to buy LED trailer lights and then remove the outer lens plastic from the light. now you have a LED array you can use in your car. Now these arrays do not have the 7443 style sockets, which are wedge shaped. they only come with three wires attached to the circuit board. if you remove the tail gate and look at the wires leading to the tail light sockets in the car, there are also 3 of them (one is for brake; tail light; ground). you will need to cut the socket off and splice the wires from teh LED array to the wires in the car. make sure to wrap in electrical tape.
the most difficult part of this procedure is that the tail light plastic must be separated from the main housing so that you can insert the array. the tail light is made up of 2 parts: the red plastic and the housing (attached to car), which are sealed together. the hole in the housing is only big enough for one bulb and there is no way you can get any LED array through it. you must use a sharp blade to pry the 2 pieces apart, mount the led array with some hardware between the housing and plastic cover, run the wires through the hole the bulb, and seal it back together with silicone.
this is a great way to get bright LEDs into your LX. i definitely plan on doing it too. so my suggestion is that you do the second way; but, if you're really not into cutting wires and stuff, just go to the website and order the tower bulbs (they are the brightest they offer).
most important thing to remember is that though all the stock bulbs are that whitish-yellowish color behind the lens, when getting an LED bulb, you must match the color of the bulb to the color of the plastic it will go behind. for example, when you pull out the stock tail light bulb, it will not be colored. but you must buy a red LED bulb. do not buy white LED bulbs for anything but the reverse lights. buy amber for the turn signals. it's very important that you remember this.
also, some of you have brought up the fact that the faulty bulb sensors will light up when the LEDs are in place. When i replaced my stock bulbs with LED bulbs, the only problem I had was with turn signals, which blinked quickly. to solve this problem, you must buy a load resistor. the turn signal wiring harness consists of 2 wires. the resistor, pictured here
http://autolumination.com/equalizers.htm you will need to buy the one furthest to the left. as you can see, 2 wires emerge from the central resistor. each resistor wire must be attached to one of the wires coming out of the car. here's the tricky part: the wire has no ends to it. what you need to do is remove some of the rubber covering on the wire in the middle of the wire without cutting it. once wire is exposed, you can just twist it together with the resistor wires. wrap in electrical tape.
hope this isnt too confusing. really guys, i'd go for it and do it if you ahve the money and time. it's a nice project to do and will definitely improve the car's look. im not even thinking about doing it anymore; i've already made up my mind and am just waiting for some free time.