Check your fuses.

 Last week I took a job, driving an older peterbuilt.  This truck had seen better days, its oil was

seriously low, so I added three qt's.  The turn signal lights did not work, due to a blown 20 amp fuse, 

looked around in the cab and found a 30 amp. The regulator was missing, but the new one was sitting on

the floorboard, so I push the three pronger in. It worked, the lights turned left and right, emergency lights

worked, ausome!   The cab was dirty, I cleaned out the trash, and was on the road after inspecting the

rig.