So I bought a 2006 Saturn Ion 3 for $1000 expected there to be a few issues the one that seems to be bothering me the most is the odometer and the trip odometer dont change mileage. It is a digital gauge so I am at a loss for what to do. The speedometer and all other gauges work fine just not the odometer and trip. Any help with this would be greatly appreciated.

 

Not an Ion expert, but from what I have read, the mileage is stored in the BCM, and the digital odometer in the IPC is updated with data from the BCM.
The IPC stores the last reading it received from the BCM before either the IPC was separated from the original BCM it was matched with from the factory

if the IPC (Instrument Panel Cluster) is changed out with a junkyard cluster and NOT reprogrammed by a GM dealer to match the VIN and get married to the BCM, you end up with a "frozen odometer" that reads the last mileage of the DONOR car it came from, NOT the odometer reading of the car it was put into.
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The TRUE mileage is stored in the car's BCM, but if the BCM detects that the IPC is not configured as the original IPC or a validly reprogrammed replacement, the BCM will NOT UPDATE the odometer on the cluster.

If the seller did not note a "mileage/odometer discrepancy" on the title when it was signed over to you and did not discuss this lack of functionality with you, they are seemingly guilty of odometer fraud---intentional or unintentional, doesn't matter. You have every right to go after them in the form of legal action, requesting coverage of repair costs, a refund of part of the purchase price once you have the repair done and the BCM shows the REAL mileage on the new cluster.....
It's your choice whether you go at it formally or informally. I am not a lawyer -- just some dude trying to let you know what some of your options are off the top of my head.....

Document EVERYTHING about your purchase including mileage at title transfer, mileage now, and functionality of the rest of the IPC.
Take a cellphone video from the back seat driving down the road demonstrating that the odometer does not move after several miles of driving.




Call a GM dealer, explain to the service writer that the odometer is frozen.
Ask them how much to reprogram the existing one in the vehicle. They will ask you if it is the original or a used one
Say you don't know, but if it is the original, how much would it be to reprogram it
They usually refuse to reprogram the used ones because then they will get caught up in a potential odometer fraud case (expert witness) every time they do.
Get the price of a brand new programmed replacement cluster while you're at it. I would think it has to be installed in order for the wiring connections to reach - dunno.

In all likelihood if you want this fixed, and to know the TRUE mileage on the vehicle (which should be stored in the BCM), you will have to pay for a new programmed cluster.

Then you can decide how to handle the seller.