Q&A

You can check the cable pretty easily, however explaining it might be tough.
Look at this pic: http://bit.ly/sbmd8
Look at the throttle cables, the cable on the bottom is the kick-down cable. With the engine OFF, you can pull the cable lightly, it should pull freely and return freely. If it binds in any way, it needs to be replaced. Check it out and let me know what you find

Wait to do the kick-down cable just yet. There is a overdrive relay, check to see if it works. On the driver side, jack the car up and look at the transmission and you will find a solenoid with a wire, maybe two that go over the transmission and slides thru a tube to a connector that comes from floor of car. This is the overdrive solenoid. Unplug it, slide it thru the tube and use a 12 mm wrench and loosen the two bolts. Remove it and don't lose the little o ring and the larger one. Spray it with cleaner and reinstall and make sure the wires are not broke.. If the relay and the reinstall of the solenoid to check the wires, fail--there is another fix that works nearly eveyrtime---iPD, the volvo specialists, sell a "plate" that covers the solenoid hole and simply lets you get the upshift to the high gear-- the downside is, and believe me it is no big deal---you just can't kick it out of overdrive, it is always going to go into the higher gear.