First off, you've got a good year there IMO. I haven't had wiring issues on the 89s personally. You should have a b230f engine (non turbo, turbo is b230ft). Engine reliability is notorious provided you take simple care of your car (regular maintence). As to the trans, I'm not certain of the year break for the ZF. If your's does not have the push button for OD, then ppl are gonna tell ya how bad your trans is. Personally (trans tech here, so I may treat them differently), I have no problems with the ZF, just don't rev then engine in neutral or park (IF it's a ZF). The other auto is the AW (not sure 70 or 71 per model, sorry). It's a very robust auto.

All that said, I always recomend (just my way of doing things I guess) doing a full work up on a newly purchased brick.

IE:

Timing belt (easily done @ home), While in there I always check seals for signs of oil leaks

Thorough inspection of all drive belts and hoses.

Clean the flame trap, it's hoses and check the flow of the oil breather box.

Inspece the throttle body for excessive oil residue (easily removed and cleaned with one cheap gasket) Likewise, the intake hoses

There are many other areas to check, but these are my first areas as they tell me quite alot about the car.

2 things I do myself to "new" bricks is flush the trans and pwr steering fluids, just cause it's so easily done and a good practice.

In amoungst all that, check anything that could cause an overheat condition, nobody likes walkin down the side of the road with their brick left behind them.

Is this your first Volvo?