congrats on the purchase, i to just bought another 1991 supra as a 2nd car although its done 130k miles but running sweet. just got the factory manual from the US to sort out my cruise con. and various other electrical problems.
have a look at
factorymanuals.com they are in the US and i paid $65 + ($60 shipping) for full tech manual, its magic, covers all, try them they might have one for your year.
happy motoring
stu