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Matt
Matt, Mechanical Engineer
Category: UK Car
Satisfied Customers: 21851
Experience:  BEng hons Mech engineering, in auto industry 22 years
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A friend of mine has bought a 1990 nissan 300 zx for his

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A friend of mine has bought a 1990 nissan 300 zx for his son. The speedometer does not work and the odometer does. I would suspect that the problem lies in the instrument cluster however the previous owner said he tried a different cluster and it had the same problem. Very occasionally it jumps up to 80 kmh (50 mph) and then just stays locked there until the key is turned off. Does the speed sensor send the same signal that is used by both the speedo and odometer?

Hello

there's a test you can do to prove if the cluster is OK or not

https://www.youtube.com/watch?v=kN-ADY1FBvY

they are prone to the speedo motor failing on these, so its possible the replacement was also bad

Customer: replied 10 months ago.
OK thanks. I was viewing that already but haven't tested it yet. Is it the same wires that send a signal to the speedo and odometer?

hello

its the same signal wire that powers both but the speedometer motor can fail independent of the signal wire

Customer: replied 10 months ago.
Do you know if we find a cheap used one in the states can it be switched from miles to kilometers per hour easily

I've not tried this myself but this procedure should change the odometer from miles to km

1. Turn the car on
2. Put the car in reverse
3. Open the rear passenger side window all the way.
4. Turn on the rear window wipers to INT.
5. Back the car up 5 feet (no more, no less!)
6. Turn the radio on, and change the channel to 99.9FM
7. Put the car in forward.
8. Turn the rear windshield wipers off.
9. Turn the volume up to max.
10. Move the car forward 4 feet.
11. Close the rear passenger window.
12. Shut off the radio.

If all has worked, the trip computer should now be in metric. Good luck!

Customer: replied 10 months ago.
Do you know if that will work in reverse. Ie: change the old one to mph before he buys a new used one to see if the process works?

I think you just repeat the process to toggle between the 2

Customer: replied 10 months ago.
Sorry meant to ask you. Does that work for both auto and standard?

hello

yes it should as its the same cluster

Hi

do you still need help?

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Customer: replied 9 months ago.
Sorry he went out of town for a while and I kind of forgot about it

understood

if you're happy with my advice would you mind rating my answer?

Hi

do you still need help?

Bear in mind that the site takes a deposit from you at the beginning and this is held by the site until you rate my answer at which point the cash is split between the site and the expert. I am only paid for my work on this question if you rate my answer, using the star system at the top of the screen. Please do not forget! Thank you

Matt and other UK Car Specialists are ready to help you
Customer: replied 9 months ago.

Sorry about not replying. When I went to close it it said payment unsuccessful even though I always pay with paypal. Even Just answer could not figure it out and they were going to look into it and they said it would take a few days. I didn't hear anything back and then I completely forgot about it. I passed your info onto my friend and not sure what he did with it. No news is good news maybe. Once again sorry for not rating you-hopefully it works now.