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Discussion Starter · #1 ·
Disclaimer: please don't do this if you are uncomfortable doing it nor please don't blame me for your action. This is my experience to share and all myself.

Hello there,

I recently purchased an awesome, nearly mint, 1988 Honda Prelude BA5 with 4WS. The car is perfect in everywhere except for two annoying things, which were totally legitimate back then but feel a bit archaic today.

1) Annoying buzzing sounds when hitting 68MPH (110KM/H)
2) Radio frequency limited to 76 to 90MHZ (like all Japanese cars)

While I replaced the radio with a double din (after some serious mount research), the speed sensor really drove me nuts. I admit that I live in Washington State (where driving 55MPH is considered being a menace to society), but even by local standards that speed sensor buzz is pretty annoying.

Long story short, I went on a search how to remove those Japanese speed sensor amplifier and quite honestly, I couldn't find anything. There were a forum few posts with "just unplug it" and the expected response of "duh..." but I couldn't find anything reasonable to work with. I therefore went on a discovery journey myself and want to share the outcome...for generations of Japanese Import enthusiasts to use. Here we go:

  1. That annoying thing is called the speed sensor amplifier - not speed buzzer, speed alert, governor, etc.
  2. It is located behind the instrument cluster (see below), requiring you to remove the cluster entirely
  3. There is no easy cable or plug (at least on a 1988 Honda Prelude) but you have to solder it out.
  4. Here is how:
Step-by-step guide:
  1. Remove the top cover of the dashboard (above the instruction cluster)
  2. Remove all the buttons for headlights, etc.
  3. Remove the button panel (where the air vent is)
  4. Carefully remove the instrument cluster connectors from the top (three big massive yellow plugs)
  5. After removing the top connectors, you will get excited to remove the cluster but you can't due to the speed sensor being mounted and you have no idea how to reach it with your fat fingers (I am reflecting on personal experiences)
  6. Carefully remove the speed sensor from the bottom mount (below steering up and up) (you cannot reach it from the top) by using a flathead screw driver and pushing it out - there is no screw, just tension. See picture 1
  7. Then you can finally remove the entire cluster
  8. Mounted on the rear of the cluster, you will find a square plastic cover where the annoying little buzzer is embedded in. See picture for square 2.
  9. Open in up by removing the screws
  10. Once open, you fill finally see a black plastic round shape -> the buzzer! See picture 3 & 4
  11. You can test it out by using a 9V battery with two cable clips to set it off and see whether that is sound that drives you my case it was.
  12. After a few final eye twitches from the sound, you will soon realize that the buzzer is soldered onto the board.
  13. Simply heat up the contact with a soldering iron (don't use a heat gun on full blast due to burning everything around it) and carefully remove the buzzer -> that's it.
  14. Put everything back together - be especially careful with remounting the speed sensor, don't forget to plug in all the connectors and you are done.
  15. Start your car, go for a drive, pray to god that the speedo still works and enjoy a buzz-free ride above 68MPH.
That's it - it is super simple once you realize what you are looking. In addition, you can also use this guide to replace your buzzer in case is breaks...making my instructions more legal I guess?

Either way, I hope it helps some and again - no guarantee that this works. It worked for me but experiences may vary.


Picture 1 - speed sensor mount


Picture 2 - Speed sensor amplifier

Picture 3 & 4 - amplifier AKA the culprit


230 Posts
Is this part related to the part that fell off your car which you asked about and left everyone hanging?

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