The low beams are not fused separately so it's pointless to go looking for fuse problems.
You need the factory service manual's diagnostic information for low beams in-op. It's on page 8-275 in volume 3 of the manual set.
Briefly, in a case where low beams are in-op and high-beams work, you're going to be looking for a short-to-ground, an open or a high resistance in the headlamp wiring or you're going to be looking for a faulty multi-function switch in the steering column. The FSM contains information on how to determine what the problem is.
If you end-up having a bad multi-funciton switch, and you're DIY, once you start working on the steering column, follow service manual procedures to the letter when working on the air bag system. Failure to do that may result in injury or death of the SIR goes off unexpectedly due to improper service procedure.