Old GT timberline shifters don't work

[pete in atlanta]

Evening all:
I bought my wife a GT Timberline mountain bike back in '95 as a graduation gift. She rode it twice and put it to sleep in our basement. Well now we're getting back into cycling and I need to tune her bike up. I've got everything working except the shifters. The bike has Shamano Acera SIS shifters and derailers. The shifters have two levers- one to raise the gear and the other to lower the gear. Both levers seem to have no tension but the cables do not appear to be broken- as I can yank on the cables along the lower frame tube and the derailers move. What do I have to do to get these shifters to work?
Thanks for all your help.
Pete

 

[percious]

Probably the cables have stretched from years of sitting there. Shift the shifter to the lowest gear. Can you pull slack in the cables? If so, follow the cable back to the derailuer. Find the bolt that tightens the cable to the derailleur. make sure the chain is on the smallest ring, and then loosen the bolt that holds the cable to the derailleur. pull the slack out of the cable, and then retighten the bolt. then see if the shifter works again. If it does, you can fine adjust the shifting using the barrel adjusters on the shifter. If you can't figure out how all of this works, bring the bike to the shop, and pay them 30 dollars to tune it up.

-percious