I recently purchased a used '97 for my son. The badge on the trunk says "S90", but the VIN search shows a 960. How can I be certain which it is? Are there any telltale signs that one or the other has?

Also... Since the day we bought it, the "Service" light has been on. It's only on for the first minute or two after starting the car. I did a google search on how to reset that, and found resetting instructions for '99 and up models, but could not find anything about resetting the '97.

Today the "check engine" light came on. I'm assuming that particular light is one of those that has to be read and reset by a shop?

To reset the service light there is a small rubber plug in the cluster face. Remove it and take a small screw driver or punch and press the button behind it in. Basically the S90 is a 960. The only differences are some interior changes such as seat coverings, trim on the dash area and the badge.

if its a 97 its a 960. S90 was for the 98 year 960.

The only difference between the two is wheels and if they painted the lower plastic trim.

There was a 1997 S90 1997 was a split year for the 960/S90
The Vin will always show 960 even on the 1998 cars.

The Rear Brake pads are different between the 960 and S90.
One is smaller than the other.
Watch for that when you do or have brake work done.
One set of pads are taller than the other.

Have seen many times where the wrong pads were installed and the Rear pads cut and then held the pads from hitting the rotors.

If it is badged as a S90 then it is a S90.

The S90 was made in both 1997 and 1998. If it says S90 on the back, more than likely, its a S90 (cant see why someone would go to the bother of changing the back emblem from a 960 to a S90)...though, they are very similar. :57:

Am I right in thinking that for the engine type bit on the VIN, 95 is the 204bhp and 96 refers to the 184bhp version?

Yes, that's right. 95 is the 204 bhp B6304S and 96 the 180 bhp B6304S2. At least for the european market.

There aren't many differences in the 960 and S/V90, but there's one in the interior: the buttons for the seat heating are behind each other on the right hand side (left hand on RHD cars) of the handbrake on a 960, and either side of the gearstick on a S/V90. The skirts and bottom of spoilers weren't painted on both standard 960 and S/V90. Colour-coding was optional, at least in the dutch market.
Otherwise, many 960's that were standing around have been updated to S-V90 by dealers, but the interior seldom, if ever, was changed.