Hello, pretty new to the forum but have been wrenching on Lexuses for about 8 years. Owned many models from sc400s, ls400s, is300, and sc430. I am pretty up to date with how this cars work so i need some expert advise.

i purchased a beautiful 1990 ls400 for almost nothing and i knew exactly everything that was wrong with it upon purchase why i probably got a good deal. Car only has 125k miles and it looks like it on from the inside and out side. Car was not drivable at first it had air ride that failed so replaced that with strut masters, and replaced the power-steering.

upon driving it around I noticed the odometer had stopped counting. So I ordered parts did some research i took my odometer apart to my surprise the gear that is in the odometer was still intact. I continued to take everything apart to inspect it more and seen that it did have a tiny crack across the gear. I then tried to to spin the gear it seemed stuck probably due to crack so i poked it with a flat head it fell a part. So i replaced the gear. Put the cluster back in and took it for a test drive still not working

is there a way to bench test this motor to see if its working?

 

Still having trouble with my 1990 ls400 odometer. Replaced gear. Still not working. Is there anything else that controls the odometer i cant find nothing online

 

merged the threads. no need to start a new one on the same topic.

unfortunately i don't have any experience with any bench testing of the odometer but our resident electronics expert @Yamae may be able to assist!

 

Thanks for the reply. i just want to get it taken care of as smoothly as possible. When i took my gauge cluster appart to get to the odometer it through my temp gauge off and im pretty sure its getting stuck now 😤 so thats now another problem i am facing with it

 

I worry that your's may have a electrical problem. Have you checked the pulse motor and it's drive signal? Does it spin when you run?
https://www.clublexus.com/forums/att...r-odometer.jpg

 

How would i test this motor? I haven’t took the cluster apart again i just want to make sure i do it correctly

 

You need some fundamental electrical skills to do this but simply apply the motor the pulse signal which swings O to 5V and it should spin every time the pulse is applied. Or simply extend the wire harness using insulated wires and run the car to see how it spins. When you do this, you need to remove at least one of gears though. If you are not comfortable doing this, you will need to contact some professionals.

 

Replacing that gear was a pain

 

i have some electrical skills. I dont want to cut the wires and extend them. So if i remember there is a yellow and black wire with a white stripe. Can i connect 9v battery or even 12v to the the two wires to see if the motor will spin?

 

It's good that you have some electrical skills.

You can use a 9V battery but you'd better to put in a series resistor of 22 ohms or so. If a 22 ohms resistor is not available, use a small incandescent bulb to limit the current. Just apply the voltage for less than 0.5 second and stop it and then re-apply the voltage. Repeating this should make the motor to turn some every time the voltage is applied, if the motor is not dead.

If the motor is OK, the next step would be to check the drive signal from the cluster board. It would be the best to use an oscilloscope to observe the drive signal.

Another thing you'd better to try is to rotate the gears manually one by one to see that there is any mechanical problem exists.

 

Thanks for the information yemae! I definitely will try what you said off to the the electronics store. I have checked the mechanical movement of the gear like i said in the beginning my original gear seemed to be okay but did have a crack in it but when i did try to move the gears there was no play in the system idk if that is normal or not but i think it could of stopped the motor from spinning burning it up but I don’t 100% remember. Now i know to take notes.

when you say check pulse are you saying to check signal pulse from the computer? Like with a test light?

 

It would be the best to use an oscilloscope to check the drive signal. The waveform is something like this at the middle of the link. This link is from the page below although everything is written in Japanese.
https://techcompass.sanyodenki.com/j...001/index.html

Another method is to confirm the signal by your ears using an audio amplifier and a speaker connecting the drive signal as an input signal. You need to attenuate the signal level about 10 to 20 dB to match the level. Or simply connect the headphone to the drive signal with a series resistor 100 to 1000 ohms to protect the headphone/driver and your ears. In other words, you can check the drive signal as an audio sound.

 

that is some really good information I appreciate it. And thanks. i can translate some of that too to understand. Sorry I haven’t got back i been super busy working on cars. Its never ending sometimes

 

Yamae do you have any idea what is going on with my temp gauge messed up since i took the cluster appart. It will not go back to zero. Its almost like its off calibration and its reading over the halfway when car is warmed up. Its really irritating how delicate these parts are its like a gust a wind or me holding it upside at some point made gauge not go where it’s supposed to be.

 

That is with. The car completely cold