I've searched far and wide for the answer to this...... My instrument cluster in my 97 Deville is broken. I'm bidding on one from a 99 on ebay. Will it work? It's too late to retract my bid, but I'd like to know, regardless. Thanks.
The bad news is that I don't think they are directly interchangeable. They are outwardly similar (in appearance) but there are differences in the firmware between years - My borhter has a 99 and my mom has a 97 and having "messed" around with both cars, I can tell you that there are functional differences between the two years.
It seems that the clusters change internally almost every year, even if only slightly and thus interchange between model years is usually a no-go.
The other problem I foresee is that the 96 and up OBDII/class 2 communications based cars have the vehcle VIN, manufacturing data and such stored in the cluster for verification. If the data doesn't match the rest of the car's modules it may not come up at all, and even a cluster of the same year probably needs to be "flashed" with a tech 2 tool to get it working right.
Hopefully, someone else here can speak from experience on doing a cluster swap, I have a 95/OBDI and it is not nearly as complicated on this car as the 96 and up.