Leaderboard

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!

@jiggity76, a remanufactured cluster would be a solution, after some odometer transplantation work to keep the mileage of course. I assume that a remanufactured one will also have just a resistor added in order to replace the faulty one between pin 4 and 10 on the infamous white resistor IC (I do not think any 100% accurate original ones still exist). I should maybe ask the Ebay seller if they indeed fix them like that, if it's not to much of a trade secret. As said in my initial post, I live in Europe, so by the time all transport and taxes are paid, a replacement cluster is quite expensive, knowing that repairing my cluster is possible with some soldering work and a 1$ resistor. So that seems to be the best option in case a neat & quick solution is not available (like a replacement for the white resistor IC as Batee makes for Corvettes, or a circuit board as can be found for many other models on https://www.cajuntachshop.com/ ). So I'll try to do that fix, many others on the internet did just that with success. But I remain curious about the effect of degradation of the other black field on the white resistor IC and any documentation would be welcome, I only have the service manual of the car.

I enjoyed reading your thread here but I must admit that I'm a moron when it comes to electronics. You might as well be speaking Japanese to me. It's not your fault of course, it's definitely mine. Typing in that number on Ebay, this cluster along with 2 others popped up. This one though is a remanufactured unit. Maybe they is a solution thru this place? https://www.ebay.com/itm/124970672582?epid=26044439203&itmmeta=01HY9CCXBWVEKDBMQQ8P48BCGR&hash=item1d18d521c6:g:XMcAAOSwXvphdbou&itmprp=enc%3AAQAJAAAA4FvtXGhD3ynH%2FUR99gvrGyqpTrQlhnDyASk4eK4%2Fca4OOv6UKXx8PdOAyy%2FJXd3WMC0hivWON5tM5qLEs1dWmPx1EZ93EfcAB%2F%2BzJ5eZEvpxetPo6IIUMG9MT8OPMPQIcO%2BjpkzL%2FaQUte7afW4dnVEX7u%2B98Fy0mu75s5zL%2FRRVZAjq02LztCqfEyXJT09vgK%2BUnLtDo6NivgaICJxkRsB%2Fiy4y%2BwWsfIEQ4oIvDKd1qHxaifOZrp8N7VtlfiBc0bs8chKKpuww9TKZKQRFgUXj4X%2BTx%2FyCYrTQXudxf8%2B4|tkp%3ABk9SR_zVs6zyYw