BROKEN ODOMETER - IF REPLACED, WILL NEW UNIT SHOW MY CAR'S MILEAGE

  • Tiny
  • cmayo
  • 1999 Pontiac Grand Am
  • 60,000 miles

I just bought an almost-pristine 99 Grand Am and the digital odometer doesn't work correctly. With the lights on, random odometer digits will light up, but not consistently and I can't tell how many miles are actually on the car.

I found a YouTube on a similar problem with a '99 Buick Century (http://www.youtube.com/watch?v=jTQIVS_uB4g) which suggests that a set of resistors need to be replaced, and I may pull my cluster to see if it's laid out the same and try replacing those resistors to see if it helps.

Otherwise, there are several used clusters available on Ebay at good prices and the cluster replacement looks pretty easy, but if I do replace the cluster, will the replacement cluster automatically show my car's mileage or will it need to be programmed somehow?

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Thursday, May 31st, 2012 AT 1:46 AM

8 Replies

  • Tiny
  • ASEMaster6371
  • Expert
  • 25,556 posts

No, it will display the donor cars miles. To program it, you will have to either send it away or have a dealer do it, if they will do it for you. Either way it will add considerable cost to you.

Check on a reman unit that the seller can program the mileage for you.

Roy

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Thursday, May 31st, 2012 AT 1:51 AM
  • Tiny
  • cmayo
  • Member

That's what I was afraid of. Guess I'll look at those resistors before I decide whether to replace the cluster. I haven't had any luck finding remanufactured units but will search again if I decide to go that way.

Thanks very much for the answer!

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Thursday, May 31st, 2012 AT 2:27 AM
  • Tiny
  • saturntech9
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  • 29,420 posts

Just to add to this one from what I know about programing mileage on gm cars if its stored in the speedometer or the body control module once the mileage is put in the new part it cannot be changed to read a different mileage. So if you get a used part then your stuck with that mileage.I know saturn chevy gmc thats how it works.

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Saturday, June 2nd, 2012 AT 4:54 PM
  • Tiny
  • saturntech9
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  • 29,420 posts

Oh and pontiac atleast the later model cars.

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Saturday, June 2nd, 2012 AT 4:54 PM
  • Tiny
  • cmayo
  • Member

I bought a used cluster with similar mileage off Ebay. It arrived today and after testing the cluster to make sure it worked correctly, I tried replacing the circuit board on the replacement cluster with my original circuit board and, after re-installing the cluster in the vehicle, the odometer showed the original mileage for my vehicle.

So at least in my case, my car's mileage was stored in the cluster's circuit board. Since my odometer issue was apparently a defective LED and not a bad circuit board, pairing my functioning circuit board with a functioning LED odometer readout fixed my problem and my odometer now shows the correct mileage for my car.

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Wednesday, June 6th, 2012 AT 12:42 AM
  • Tiny
  • saturntech9
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So was it just the back light for your odometer that was out?Also that car has a body control module so I would say your mileage is stored in your body control module.

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Wednesday, June 6th, 2012 AT 1:16 AM
  • Tiny
  • cmayo
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No, not the backlight, it was apparently the LED itself or some other component inside the housing. I didn't go into the housing itself, just pulled the rear cover and swapped the circuit boards.

I don't know about the BCM. When I tested the replacement cluster it read the mileage the seller said it read, 59, XXX. After swapping the boards, the replacement cluster reads what I think is the vehicles actual mileage, 54,564.

If the mileage is also kept in the BCM, that doesn't seem to be where the odometer gets it's number from.

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Wednesday, June 6th, 2012 AT 1:58 AM
  • Tiny
  • saturntech9
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  • 29,420 posts

Then maybe that mileage is stored in the cluster board glad to hear you got it fixed.

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Wednesday, June 6th, 2012 AT 2:40 AM

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