DIY: Killing your warning chime with style (1 Viewer)

Ayune

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Portland, OR
One of the first things I did when I bought my '98 LC was to exhume the warning chime from the instrument cluster. I ripped it off the circuit board with impudence and reveled in the silence...

However, after reading about brake booster failure and its accompanying audible warning, I thought "I'd sure like to hear that warning if/when it happens". Assuming there's no other dedicated "kiss your ass goodbye" noisemaker in the dash, I decided I'd better replace the one I ripped out.

I ordered a replacement buzzer, soldered it in, and quickly realized that I need to figure out a better solution: The open-door/seatbelt-off/key-in-ignition warnings were way too much. [BTW, TechStream doesn't offer any silencing options for the early years.]

So, what I did was find the chip that controls the buzzer and change it to be powered from the "D" light instead of from the Gauge circuit. So now the buzzer can only sound if I'm in "D", the gear I'll most likely be in if/when my brakes fail.

Here's a rough overview with pics from my '98 (should be the same for '98-03?):

- Remove the instrument cluster, and the rear white plastic cover.

- Remove the left green circuit board with the "4WD" and diff lock lights, by unplugging the connectors and removing the screws.

- On the right circuit board (the one with the big black buzzer) locate IC2 (marked “10358” in below pic). This chip controls the buzzer and gets 12V through its pin 8, the corner pin above the “1”. The round circle molded into the chip denotes pin 1, and the pins are numbered counterclockwise. I buzzed out the traces and found that pin 8 connects through the fat trace above it, so it needs to be cut and scraped so you can 1) disconnect Gauge power and 2) solder a wire to it with “D” power. In the pic below it’s already cut & scraped, and now copper-colored.

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- Since circuit boards do get revised if your board looks different that mine simply follow how IC2’s pin 8 gets powered and find a nearby trace that will not disconnect anything else when you cut it.

- Using a small knife gently scrape the green coating off this trace to expose the copper. Cut the trace at the right side of the trace shown by the red line below. Gauge power feeds in from the right so after the cut the left side of the trace is only connected to IC2. This is where you’ll feed in “D” power.

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- On the circuit board that you removed, solder a ~4" wire to the pin shown below. This is the 12V that goes only to the "D" light.

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- Re-install the left circuit board, connectors, and screws. Solder the other end of your wire to the exposed copper trace near IC2. Be sure not to use too much solder or you may re-connect the copper that you cut before.

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- That's it. Now your buzzer will only sound if you're in "D".
 
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