You need to pull out the dash cover that has clips then there are 4 screws holding the dash on. Pull out the dash and unplug the connector from the top. Pry the clips off the back and pull out the circuit board straight up. Mine was missing one of the resistors. I measured one resistor at 150 ohms. I had on hand a 180 ohm resister and soldered that in and it works fine.
The odometer and speedometer both work off the same circuit. If you loose the odometer and the speedo still works, you have a bad instrument cluster. Here's the diagram I am talking about.
the gear selector and odometer are right under the speedometer.
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The odometer works in this manner;
Signal is sent from the speed sensor to the computer. Computer sends the signal to speedometer and counter (located in the instrument panel). The signal from the counter is sent to the odometer for display.
The gear selector gets a signal from the transmission range switch. Power is provided from the ignition switch.
Since your speedometer is working, your odometer is not. This can't be due to a bad pcm signal. It does not matter if the counter or odometer display is bad because the instrument panels only come as one unit. I suspect the little panel that has the odometer and gear range display is faulty.
The instrument panel needs to be replaced. They are not servicable (not repairable). After replacement, the odometer counter needs to be programmed with the correct mileage.
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The odometer must be reprogrammed with a tech II scanner or something equivlant. It can also be programmed by certain manufacturers. If you have the scanner, you can save the information on your car's computer/ make sure it is saved and reprogramming will not be necessary.
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but the odometer & gear indicator display is an LCD. If it isn't lighting up, it is dead as a module. There is no backlight to replace. When I got down to mine, I could see the location of a burn-out on the LCD. It's possible the same happened to yours. I was hoping to replace just some back light bulb but it's just not possible.
I haven't found any reputable dealers with instrument clusters for sale, though there were a few on eBay. I don't know if I want to put those into my car though. I'm just going to call up a dealer and see how much it'll cost to have them install a new module. (Probably too much, but I'm kind of over a barrel on this.)
There is online video showing how to repair the resistors.Click this link and see the video.The repair is for 2004 model Buick, but will help for 200 Buick also:----
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but if replacing the resistors is not helping then getting the instrument cluster board replaced is advisable.
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COmment by the reader:----
Thanks techno. I have a 2003 and 2001 buick Century and this fix worked great for me on both buicks and even easier than I thought. You don't even need a solder sucker to clean out the old solder because the pins don't go through the board. Just curl the wire under, cut to right length and they sit right on top. Odometer bright again. Thanks again. ---------
