how do you turn off the traction control

You probably cannot. The traction control is obtained by manipulating the ABS system. It is not driver controlled.

Why would you want to do this?

There are many reasons to disable traction control. However, before the OBD I (1994 I believe) there was typically no button available to do this. However there were some obscure methods to accomplish this. Check out this link to see how someone with a 1994 Cadillac was able to disable TC: http://caddyinfo.ipbhost.com/index.php?showtopic=4814

Button in the glove box