Tony,

What you describe sounds like a check valve problem (common on Volvo's). Raise the hood all the way and at the bottom where the hoses go to the jets take the center hold down (oblong) for the hood liner out (twist 90 degrees) pull back the liner carefully, (they are fragile with age + the heat) stick your hand up in there and there is a red and black check valve there that is clipped to the hood framing with the hoses. Remove the hose and check valve (not much slack or play), replace the valve and you should be OK. The check valve part number is 1392074, parts calls it a delevery valve. Incase your jets have gotten clogged from age or wax and you can't clean them out with a wire, the part number for the actual washer jets (black) is 9127605.