89SE Posted May 31, 2023 Report Share Posted May 31, 2023 (edited) The analog tachometer of my 89 Grand Prix SE works, but indicates about 3 times the value it should. The cluster is 25122113. The 3 small gauges seem to be working fine, the speedometer is digital and just fine. I hear the analog gages are a common problem as on TGPs. I also read it is usually caused by a faulty resistor. The tacho does not have a calibration resistor on the Air Core motor itself, but there is one on the circuit board. I live in Europe, so getting a refurbished instrument panel is quite difficult/expensive for a gauge that is strictly speaking not necessary, so I am looking for a cheap and easy fix. I am not 100% sure yet, but the culprit is most likely to be a calibrated 14 pin ceramic DIP resistor (the white and black on the picture). Since it is not a speedo, calibration is not the most important to me, so if I could get a replacement with about the right values it would be probably a good enough fix. Anyone here has the specs of the resistor? I have found a replacement for a similar resistor, one for Corvettes: https://batee.com/collections/1990-1996-corvette-parts/products/90-96-analog-calibration-ic-adjustable-preset-for-6k-tach So if there would be a source for the version used in the Pontiac GP, please post it here! Edited June 2, 2023 by 89SE Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.