1991 Chevy Lumina Trun signal flasher

Electrical problem
1991 Chevy Lumina V6 Front Wheel Drive Automatic 80000 miles

My friend just rear-ended someone in her 1991 Chevy Lumina sedan and we are in the process of fixing her damages. The problem that has stumped me is that her 4 way flashers work, but her turn signals do not flash, they just stay on. I am thinking that there are 2 flasher units, one for the 4-ways and 1 for the turn signals, but I can't find the flashers. Am I correct in assuming that her turn signal flasher is bad, and if so where is it located? I can't find any flasher units in the fuse box under the hood or in the passenger compartment. Thanks.