Saab Wiring Diagram 9 3 - GM Specific Models. 2002 Cadillac STS I looked under the hood and popped the cover off the fuse box. Under the lid is a diagram of the fuses with labels. One of them (#24 on my model car) said "DRL" on it. I pulled that fuse and voila!. The camshaft position sensor is used to synchronize fuel injection and as a feedback device for VANOS (variable camshaft timing) control. When a camshaft sensor fails, the check engine light will illuminate and a fault code will be stored..