Speedometer Needles Suddenly Go Out?

[90LS400Lexus]

I was under the impression that the instrument cluster needles on these cars "gradually" go out- not out all at once. Well, more bad luck for me has proved that they do instantly go bad, even in 90 degree weather. I went to Wal-Mart a little while ago- all needles working fine. I left Wal-Mart and got back on the interstate heading home and while accelerating on the acceleration lane, I looked down at the tachometer and then noticed that only 1/4 of the speedometer needle was illuminated. When I turned the brightness level down on the dash, the needle started flickering. I was also under the impression that these typically are noticed to be going bad when it is cold outside, but it was 92 degrees at the time (still 91 degrees) and it started doing it. It was fine this morning when it was 65 outside- now at 92 degrees, it stops working for the first time. Is there a chance it will start working again. You all know I have this car for sale and it irritates me that something else has happened to lessen the value even more. Just my luck. Thanks in advance.

[CUMan]

The dimming of the needles is a separate problem. It is not related to the well-known propensity of these dashes to fail to illuminate when the weather is cold.

The needles have a conductive material on the back. This material tends to crack after years of use. The loss of illumination would depend upon where the material cracked. If the break was near the pivot point of the needle, the rest of the needle would be dark.

My 93 LS 400 had both of the problems. My dash would not illuminate when the weather was cold, and my speedometer needle was dark about one-third of its length. I sent the dash unit to Jim Walker in Fresno, Ca. last December, and he fixed both problems.

[90LS400Lexus]

Just fine- just my luck with this car. :( Now I guess it is broken. Would hitting a large pot hole cause this? Before I got onto the interstate- I was was on the loop to the freeway entry that leads out of the northwest side of the city. I remember hitting a fairly large sunken in manhole with the left front tire. Normally, I dodge this hole, but this time I was switching lanes and hit the stupid thing. I do not remember looking at the speedometer until I left Super Wal-Mart and got back on the freeway. Perhaps it "finished" it off then. 1/4 of it is still illuminated, but the other 3/4 "flickers" when the switch is turned to lower illumination, but when it is switched to "bright", or when I turn the headlights off, it will go completely off on that end. I guess it is finished (for me anyway), because I cannot possibly spend another dime on this car. I am already losing money anyway, offering it at $3400. Now that this has happened- I guess I will list it in the paper tomorrow for $3000- $1400 less than I have invested. <_<

Thanks again.

[90LS400Lexus]

Well, the needle light actually started working again for a while today, but it stopped again. I guess it is finished. Thanks again for the reply.

[Lexls]

Yeah, hitting a pothole would do it. The problem is that the backing on the needles becomes brittle over time and the adhesive deteriorates somewhat. A major jolt to the car can cause this backing to crack. When it's cracked the needle won't illuminate fully. The good news is that they can be fixed, but I don't know how....yet.